I missed out on the Gto's as well, as far as i see its a good deal. even without the MIR it's one of the lowest prices on the net for a GTX, most stores are selling them for 400+, only open box or refurbished cards are selling for less than 400.
I have an MSI 7600Gt which is considered the fastest 7600Gt, and it has HDCP so as far as how they stack up with the other VGa card makers, i'd say they're up there with the best of em. Not to mention it seems they are the only company with a G80 out right now. As for their rebates i can't say, i sent in one a month or 2 ago and haven't received it yet, but they did say to expect at most an 8 week wait.
Don't wait too long to build that system, waiting too long is the reason i missed the GTO's when i finally made up my mind to get one they were all gone. At the end of the madness Mwave was selling off the last of the GTO's for 319, so i'm not too hesitant to pay an extra 60 for a true GTX guaranteed to have 1.1ns ram. Newegg is sold out of every single GTX model they had, and with the G80's on the horizon don't expect to see them around for much longer.