Most will say go for the nVidia card and in all fairness they do OpenGL pretty well but saying that I use a AMD card (a factory overclocked 7870) and have done so for many years and have had no problems with a range of applications including Poser, Vue 8 Infinite, 3DS Max 2012, Photoshop (CS5).
You can have a look here - Anandtech Bench which will allow you to see the benchmarks for the various cards that you are looking at giving you the ability to compare two cards against one another.
Edit - Keep in mind that the latest AMD drivers have, apparently, substantially increased performance of their cards by quite a margin and are now on part, performance wise with their nVidia counterparts.