Mark Levinson model differences : 333 vs 432 vs 532 / H

I’m new to ML and have a chance to buy a 333 for 3k from a friend, fully restored by ML (all caps replaced). ML also has an upgrade program to replace the PCB to essentially turn it into a 336. 

Question is, are the 3xx series - given that they’re 20 years old - in the same class as the 10 yr old 432/532 series, or are 432/532 an upgrade over the 3xx series? I wondering if it makes more sense to buy a newer model rather than a 20 yr old model. I can’t really find a positive answer from the forums so wondering if current owners and experts know the real deal. Also, it seems like the H series is a budget version of the 5xx line? What would be the sonic differences between them, if any?