I very nearly bought a 4200 and had a colleague who had a 3200gt. He loved it even though the engine was plague with problems. The maser purests love the 3200 as it was the last of the Maser engines. Unfortunately major engine problems are not uncommon. The 4200 is a much better bet having a reliable Ferrari V8 with chain cams so no expensive belt replacement and pretty reasonable servicing.
I love Masers, they feel bespke, special, hadn built. A class car for class people, if you know what I mean....