From: Falkland Islands
80min discs are usually less compatible, especially with respect to older hardware (players/drives).
For newer players, such as the one in a PS2, normally there should be no problem to use either type of a disc. I think it is the quality of the disc that matters more, than its capacity.
Soon there will be a section available to our forum members for on-line media quality tests viewing. There such questions, it might be possible, to be answered more easily.
WM # CI