Save for the occasional recording overrun, which I've always blamed on the network rather than the machine (no idea if that's right), I've always been pretty happy with my 710.
I've never really experienced lockups to the extent some users do, but then again, I never really record anything from five or its related channels.
I'd have to say that I've always been satisfied with the quality of the machine's recaording and output. I did have a slight issue with DVD sound playback for a while, but I resolved it by reading the manual and playing with the sound settings. I think that there was a thread about it at some stage.
My only real gripe is that the machine is occasionally a little bit slow in responding to the remote control.
Sony's support for the product has been pretty poor to say the least, but I'm still buying Sony because the quality of the product remains (in my opinion) superior to other brands.