Analytics services: should I pay?

If you sell stuff or if a conversion to user reliably generates revenue, you should almost certainly be using Mixpanel or Kissmetrics for funnel analysis. Squeezing the problems which you don't know exist out of your checkout funnel, signup funnel, first user experience, or viral invite funnel is worth your weight in gold. A client of mine is currently prepping a blog post about their experience. It is an epic tale of sorrow and redemption... or just making a ton of money squashing usability issues no one knew existed.

I also pay for Clicky as a backup to Big Daddy G, and am going to try out GinzaMetrics in more depth one of these days.

http://chartbeat.com and http://haveamint.com are great for real-time analytics. I'd recommend them to anyone who:

1) experiences spikes in traffic and needs to adapt any load-bearing or server settings, etc. on-the-fly;

2) and/or is looking to figure out where random, but brief bursts of traffic are coming from, e.g. a foodie blogger who gets a bunch of traffic from a big food site news article and wants to jump in on the conversation mentioning them as it happens;

3) and/or has cat-like behavior and could just sit and watch meters all day.

EDIT: Also, for heat-mapping/usability testing: http://clicktale.com is good (though somewhat unreliable in my experience) and is probably the most cost-effective solution you'll find for SMB. I've never used http://userfly.com but it looks decent and seems to have gotten good reviews.

I can recommend the open source pendant http://piwik.org/. You can install and operate it on your own servers easily and all data is stored on your machines.

If you're looking for a paid analytics service then Webtrends service might be a solution for you: http://www.webtrends.com/

Omniture is worth it if you are doing at least 10 million UVs a month. Great for the Comscore plugin if you are counting on high volume ad buys.

SWIX focuses on social media metrics... http://www.swixhq.com

http://www.reinvigorate.net is looking promising :)

Whats your product?

If you want mobile social analytics then try www.pinkelstar.com