I highly doubt there is a catch. I've been with fastservers for awhile now and their service is terrific! They even offer toll-free tech support with techs that are super friendly! And they respond to trouble tickets and questions almost instantly!
I just got a fastservers.net box, and its been pretty good. The only problem was that they originally installed WHM/Cpanel (free license I guess). I might have liked that in other circumstances, but I don't plan on doing any webhosting on the box and I need the resources WHM uses, so I told them about the mixup and they did a plain RedHat 7.3 install.
So far its been great, especially the speed! I was wget'ing an app when I thought to myself: "I remember the download being bigger than that..." It wasn't that the size of the file shrunk, it was that my box got it at 8.68 megabytes/second Great speed, especially for the price.