I am a customer with both and I second most of the opinions above - Fatcow is heavily oversold, the cPanel is limited, database management is lagging behind other hosts and recently I started to receive the same ads from them and Globat, which makes me believe there is a connection (panels look the same), and let's not start a rant on globat here (I use them for junk pages, they are not able to serve anything properly.
On the other hand, Bluehost is the same company with Hostmonster, and they are acceptable. I am with them for over 3y now for some websites and the service is good.
@16 they throttle the CPU usage and might flag you on high traffic. Never had an account frozen, and I do around 2TB/mo on some. Are you sure it wasn't throttling?
PLEASE PAY ATTENTION - they are very strict on the number of files (50k/account with Hostmonster). This started in spring and people with 90k+ files had their accounts frozen. Make sure you don't let Joomla or anything similar escape the threshold. Same for catch-all accounts. Hostgator does not have exactly the same limitation - only that after a certain number of files they stop backing up your account.
Someone compared them to JustHost - careful there, JH (and Fatcow for that matter) charge for subdomains - while BH/HM don't - this is interesting if you host lots of sites and sub-sites on the same account (you don't need to pay for http://forum.yoursite.com for example).
Good luck!