i'm currently learning on both and much prefer nuendo although i'll admit i've worked on Nuendo more so I know the "ins and outs" better. But, alas, Pro Tools is still considered the industry standard and it's important that i know it as well as neundo as best i can in order to get as much work as possible.
the other reason i'm not so big on the pro tools hardware is that i'm not too much a fan of the a/d converters. We use Radar24 to track and then dump the tracks to protools using a converter cable (looks like an ethernet but is different) The Radar24's A/D's are drastically better than the Pro Tools.
So like you guys said, people tend to buy and use the gear they learned on....hence my anxiousness to get an alternative to pro tools setup with Nuendo 3