Almost everything is the same about the car itself. The powertrain is different though. Old school inline six, not as efficient as the 525, not as fast as the 540. I think the 535 is arguably one of the most durable models in the e34 line up. Engine is simple and easy to work on. Less complex than either of the newer engines and lots of space under the hood.
I like it, they are relatively rare, fun and economical to drive. Maybe scratch the economical part if you have to daily drive it in the city. I average 23-25 mostly rural mountain driving.
Current ride... '13 GTI Wolfsburg
BMW's from my past...
'92 535i/5 '89 325ix/5
'98 750iL '86 325(e)/5
'95 740iL '84 318i/5