I used Hostgator for many years with no problems. A few of my sites began taking up a lot of bandwidth and I was politely told I'd have to upgrade to a dedicated server or more expensive plan if I wished to stay with them. I wasn't too happy about it...so I switched hosts...only to find out the same issue elsewhere.
If you have a site that takes up lots of bandwidth and resources, you could run into problems with Hostgator or any of the webhosts. Their lower priced packages are for your run of the mill websites that aren't resource hogs.
I've also had one of the "reseller" accounts at Hostgator and no complaints with it.