This is a detailed comparison of Google Alerts vs. Talkwalker vs. Mention. The analyses was performed on three key points:

1. Amount of Alerts Delivered
2. Quality of the Alerts
3. Speed of Delivery

This is probably the most detailed comparison of Google Alerts vs. Mention written to date. Read the conclusion at the end of article to see which service I picked as the winner and why.

Total amount of delivered alerts:

Talkwalker pulled in the biggest amount of alerts: 391.

Second place goes to Mention.net which delivered 249 alerts, but if I would have included Twitter and Facebook results that amount would be close to 600.

Least and last was Google Alerts which pulled a total of 126 alerts. The only instance when Google was able to beat both Talkwalker and Mention.net is when it came to keyword number 6. This keyword was somewhat related to the recent "Boston marathon incident". It's as if Google Alerts was better suited to deliver alerts that come from News Sources.

Quality of the alerts:

Google Alerts:

Quality sites: 82 out of 89 were high quality
Source of alerts: Almost all of the alerts came exclusively from news sites
Conclusion: 92% of alerts came from quality sites, but almost all of them were news site, which means that important places like blogs, forums and personal pages were ignored.

I would occasionally come across a few blogs, but it didn't alert me of any forums (except for hybrids like "topix") and it completely ignored places like Yahoo answers, Twitter and Facebook, which is surprising, but for some reason there were no notifications of Google+ articles either. In this regard I would say the quality of the alerts was pretty high, but only because Google Alerts delivered results from a News sites. At times Google Alerts would notify me of the same exact URL 3 times in a span of 2 days, but this wasn't the norm so it's not a big issue.

Mention.net:

Quality sites: 133 out of 158 sites were high quality
Source of alerts: About 40% sites/blogs, 40% news sites and 20% forums
Conclusion: 87% of alerts came from quality sites

On several occasions I saw mention deliver results which did not contain the keywords entered into the alerts. It seems as if the keyword was dynamically generated and must have been present when mention initially crawled the site. The result is pages that have nothing to do with your alert.

Also mention returned pages which had my alert keyword inside their navigation. The keyword would be in either "tag cloud", "recent post" etc. but not within the body of the article which means that the actual page on which I landed was unrelated to my alert. I'm sure with some minor tweaking the Mention team could fix this. On the other hand mention.net did not notify me of web sites that had my keywords in the comment section, which would indicate that they have a feature in place that eliminates these alerts (unlike talkwalker).

Talkwalker:

Quality sites: 44 out of 121 were high quality
Source of alerts: Mostly blogs and strange wikis, with about 20% news sites
Conclusion: 36% of alerts came from quality sites. Extremely low quality results for three out of five keywords. In addition it failed to find high quality web sites that other services were able to find. All in all, only one out of three alerts came from quality sites.

Talkwalker's quality is hard to categorize because keyword number 5 and 6 produced spotless results. Almost all results were delivered on time and quality was good (almost all were news sites).

Unfortunately for keywords, 1,2,3 and 4 the results were as follows:

After reviewing the initial five results returned by Talkwalker I started getting worried about the safety of my computer. Many of the results were spam pages and at one point my browser (Opera) crashed because of some unknown Java script. A large chunk of the results were returned because people left spam comments containing my keywords, ironically it was spam comments on spam affiliate "blogs". From the looks of it they were blog networks. On the other hand it did manage to capture a few good results which other resources were not able to catch. But those results are definitely not worth the sheer amount of low quality pages that Talkwalker sends your way.

For this experiment I was using their free version, so I'm not sure if there is a way to filter sites in the paid interface.

Speed of the alerts delivery:

IMPORTANT: I wasn't using any quality filters when performing the test. All keywords are raw and each service was supposed to deliver the same quality keywords ("anything goes" in this case).

Mention.net:

Alerted on the same day: 130 out of 158
Delivered alerts on the next day: 21 out of 158
Delivered alerts late (over 1 day): 7 out of 158
Conclusion: Roughly 82% of alerts were delivered on the same day the text appeared on the net.

Talkwalker:

Alerted on the same day: 94 out of 121
Delivered alerts on the next day: 14 out of 121
Delivered alerts late (over 1 day): 13 out of 121
Conclusion: Where Talkwalker lacks in quality it makes up in speed of delivery. With 77% of alerts being delivered on the same day your keyword was published.

Google Alerts:

Alerted on the same day: 51 out of 89
Delivered alerts on the next day: 25 out of 89
Delivered alerts late (over 1 day): 13 out of 89
Conclusion: Google alerts is the slowest of the 3 services. Only 57% of the alerts are delivered the same day your keyword appears on the internet.

For some keywords Google Alerts would be remarkably fast, delivering the results on the same day as the keyword is mentioned. While in other instances there would be a week and a half delay.

How the experiment was performed

The experiment spanned across three days: 15th, 16th and 17th of April 2013. I used a total of six keywords to perform this experiment. I did NOT include any filters, so in Google Alerts I would select "Everything" and in Mention I would not apply any filters. The only type of filtration used was to take out two websites that continuously pump out articles which trigger alerts, so as to avoid clutter I have blocked them out. All three services offer an option where you can exclude certain web sites. All keywords were in quotes when I put them in Google Alerts and Talkwalker, I wasn't able to do that in Mention since it throws an error when it sees quotes.

How I did it: On the 18th of April I analyzed a maximum of 180 alerts per service. I would analyze 30 sites, per keyword per given date. For example for keyword A in Mention.net I would look at the 30 results delivered during the 15th, 16th and 17th. That means I looked at 30 results per day. Since there is six keywords that makes a maximum of 180 alerts per service (in this case Mention, Talkwalker and Google alerts). Most of the time it would be less because Google Alerts would deliver below 30 results per given keyword.

I looked at the type of results each service returned. Were they duplicate results? Where they coming from quality sources or doorway pages, MFA (Made for Adsense sites) and RSS aggregators? How quickly did the service deliver the results. For example if I opened the alerts delivered on the 15th and found out that a news article it had sent me to was published on the 12th, I would mark it as having arrived three days late.

I wish I could reveal the actual keywords used, but a signed NDA is... well a signed NDA. I sent my keywords to the SEOmoz editors and also offered to login to my Google Alerts, Mention and Talkwalker accounts to verify the data. The keywords are related to telemarketers and unsolicited phone calls in general.

Conclusion:

None of the services had a flawless performance, but in my view Mention.net came out on top.

It delivered less results than Talkwalker, but majority of Talkwalker results were from low quality properties.

In terms of quality Mention.net had a lower percentage of high quality sites than Google Alerts, but almost all of the Google Alerts come from News sites, which means that it often ignored forums, personal pages and blogs.

As for the speed of delivery Mention.net was the fastest. Mention.net also has a nice feature where it give you a preview of the results on the right part of the screen. The only drawback is that if the web-site contains malicious code it will also come through Mention.net interface, I wish they would have just taken screenshots of the web-site, this way I can see if I want to visit it or not, oftentimes spam pages are easily to identify just by looking at them. To make things worse Mention doesn't show you the full URL (which can oftentimes also tell you if a web-site is spammy or not), you are literally forced to click on a result to find out what it is. Talkwalker on the other hand will show you the URL of the page that contains your result.

I think it's best to use a combination of Google Alerts and Mention, I would also include Boardreader into the mix which is an excellent tool for monitoring forums. You can subscribe to a keyword alert inside boardreader via a RSS feed and then plug-it into your RSS reader along with Google Alerts RSS feeds to have an even more complete list of results.