Ultra = Juiced up FX - faster memory etc. XT/SE = FX 'lite' - slower memory etc. Looks like NVIDIA are trying to cash in on ATIs naming scheme...
So what are you saying! It all depends on what u are using it for software, games, overclocking. nVidia are well knowen, but there are better graphic cards out there, which are not so known to people.
The Xt is a very crappy card. The ultra isnt that good either but its a whole lot better than the 5600xt
Like I say it all depends on what you use your PC for, at the moment I have a Geforce 2 have had it for 3yrs now!
lets be honest here...nvidia are good lower down the market but ATI are simply far better than them overall