Got the eVGA Ti4600 with dualhead support - seems SWEET for such an inexpensive card. I've tested frame rates on playblasts & random mouse pans/dollys in viewports & it seems to be outperforming our Oxygen GVX210's by a factor of nearly 1.75 to 1.
I can't say I'm doing the most accurate benchmarks, since the GF4 Ti4600 is on a dual Athlon 1800+MP, whereas the Oxygen card is on a dual PIII 933, but the GF4 is certainly performing great (despite being "unsupported" by A|W).
I haven't tried any Paint Effects or Artisan stuff yet, but after 2 weeks of production environment work, the hypershade/hypergraph/multilister/viewports all seem to be working just great on a scene chock full of SubD & NURBS. I'm glad I saved the $500 extra or so it would take to get an officially supported card! I'm not saying I wouldn't be happier with a FireGL8800 or a Quadro 4, but the Ti cards definitely give a pretty great bang for the buck.