Freezes/black screens 3 times in a row trying to play Black Ops (made it 2 minutes or less, 1 freeze on cinematics and 2 on gameplay) and then I couldn't boot to windows any more, just black screen when it got past bios options. After reinstalling windows and spending a few days troubleshooting (with help from dom and argarth) haven't been able to get drivers installed at all for it but my old gtx 680 works flawlessy in my new system with all the other parts.
I got the MSI gaming Z because of the OC and reviews on it (saying close to 1080ti) so even if underclocking would work that's basically me giving away the $100 price hike vs a base card for nothing.
I'm hoping when I get the replacement it actually works (and doesn't die after a month or something, too) otherwise I guess i'll have to try to RMA for a refund instead of replacement and drop an extra $150+ to get a 1080ti or settle for a plain 1080.