I've owned several of the HF 7" bar type tile saws, used to be able to get them for $179, use them for a year, then sell them on Craigslist for $125, far better than renting a saw. With a little attention to setup they perform great, most are not square right out of the box. I don't like storing a tile saw between projects. That said the last saw I bought was an MK212 bar type saw on Craigslist, got a great deal on it, but I am getting tired of it sitting around in the way, it's a big honking beast, cuts thick stone, and has the power to run a profiling wheel for edging stone as well.
The real question back to the OP is what are you doing that you want a tile saw for? Most ceramic/porcelain installs do not require a tile saw much at all, a good score/break setup will do 99% of you cuts. Stone is a completely different discussion though as it doesn't scratch/break well at all. Then it comes to personal preference whether you want a moving table, or moving head, I prefer the moving head.