Yes, you should probably just stick with HostGator. Any host offering "unlimited" space and transfer (or a huge amount) is what is known as an overseller. Servers don't have an unlimited amount of resources to give. These kinds of companies appeal to those who are not willing to pay for quality and instead are willing to sacrifice quality for space and data transfer. Put enough of those types of customers on a server and you are asking for trouble.
What kind of problems are you having with HostGator? You don't say. As you may know, HostGator was purchased a few months ago. Prior to being purchased, HostGator was about the only overseller out there that got overwhelmingly positive reviews. Since the acquisition, there have been some serious complaints aired on various webmaster boards. I don't host with them so I don't know what kinds of problems there may or may not be.
You will run into quality problems on most oversellers. Try reading some reviews of Go Daddy sometime. If "unlimited" this and that is important to you, you may be best staying where you are and waiting it out to see if whatever problems you may be having get fixed. Odds are you will only have similar troubles, if not even more trouble, if you move to another overseller.