These aren't good boats... They're awesome boats!
Of course we may be a bit biased...
As you may or may not have gathered, the original Mariah boats is out of business, so some parts (mostly interior trim etc.) are difficult to come by. So you want to make sure any potential purchase has a well maintained interior. A lot of the other parts are readily available through Mariah's orginal suppliers, and of course all of the parts in the drivetrain are available at any mercruiser parts place.
The "Z" models were fully optioned, window defogger, power hatch, windshield wiper and a bunch of other electrical goodies.
5.0L in that boat is a nice match. I'd a bit concerned about the hours though. If it's never been rebuilt, at 700 the engine is probably getting pretty tired.
If you have any other questions or pictures post them up. There are lots of helpful owners on here to answer them.