I was with NetFirms for a few years, and I had many issues with them but I'll skip them since they are now gone - a bad memory if you will. After doing a lot of online research I picked HostGator (over HostMonster, a close second).
My old site had 4 mySql databases controlling 4 Coppermine photo galleries, 2 sub domains (free hosting for two friends), and 2 domain pointers (xxxxx.mydomain.com). I am hosting a couple of sites with galleries that I didn't want to recreate.
My biggest fear was how to move these galleries and their databases. HostGator did everything for me. I am amazed at how quickly everything was moved. I placed my order on Wednesday, it is now Friday and everything has been moved and is already reconfigured. My sites are all up and running, and there wasn't a moment of downtime. There were initially problems with two of the databases, but the service rep fixed them instantly. Also, they replied to my email questions very quickly.
I can already tell that my php photo galleries are 100x faster then on my old server. The site performance seems to be greatly improved, especially on my streaming flv movies. The transfer was 100% successful, and I am very happy with my decision. HostGator made one heck of a great first impression! I'll come back in a month to update my review.

(now comes the no fun process of dropping my NetFirms hosting plan)