I haven't had issues. I am not a liar. But then again, I have factory Mac components, and I limit what comes in and goes out. PT 6.1 with OS X.2.8 is pretty solid. The reason that mine will remain solid is the same that the Mackie console will be reasonably solid, and that it I won't be upgrading any further.
As far as the TT24, that isn't a proven console yet. I hope that it will be reliable as it will boot and operate from ram, not a disc.