I recently received my 2.8 GHz (Octo), 4 (4 x 1) GB, 500 GB HD, 8800GT Mac Pro and have been using it for one week, with not a single problem. I have put it in sleep mode several times. One time, it took quite a while to wake up (I got scared) but it did eventually (maybe like 10-12 seconds, seemed like an eternity). But it has never restarted or had any real problems. So... to answer the original question, Yes, as a Mac Pro with 8800GT owner, I am very happy (but will be even happier when my 23" ACD arrives).