If you're just looking for rank tracking, there's a few I've heard good things about (obviously, I like Moz, but I use a lot of the other features too, and am biased):
Our rank tracker also has a competition analysis tool attached--so you can get data like # of backlinks, etc. for the top 10 Google results for any given keyword.
I currently use the $100 plan on Authority Labs and their delayed reporting is incredibly frustrating. When it works it great to get detailed and exact ranking stats on keywords. When I can't get reports and keyword data is delayed 1+ days, it sucks.
- There is a version of Traffic Travis that is free (haven't used it in awhile though, and you'll see why further down the list): http://traffictravis.com
You can even export white label rank reports from it!
- Allow me one more SEO tool recommendation: although it's not a rank tracker per se, check out real time analytics service called Hit Sniffer: http://hitsniffer.com
I've been using it for almost two years now, and whatever it may not have in eye candy makes up in it's very robust reporting.
Personally, I think $99 /mnth is so overpriced it's delusional, and I suspect SEOmoz's churn rate tells a similar story.
- http://www.advancedwebranking.com/ - http://www.gshiftlabs.com/ - http://authoritylabs.com/
Hopefully those can help! And eventually, if you get deeper/broader in you marketing software needs, maybe we'll be worth another shot :-)