I have a 98-E320 for over 4 years and put about 35k miles. So far I enjoy it a lot, the problems you mention:

Rust. - Not a problem down in S Florida
Cracked dashboards - Not for me, but it maybe since I've to sacrifice my garage space for children's toys
MAS sensors - Not a problem (yet?)
catalyst replacements. - No problem
leaky steering racks. - No problem
spring perches. - Not a problem in S. Florida
creaky seat frames. - A little but mangageable
leaky diffs. - No problem
broken sway bar links. - Not a problem (yet?)
crank shaft position sensors. - Not a problem (yet?)
m112s that eat oil - Not a problem

But the problems that I had was:
1. Noilsy packing sound from alternator - didn't need to but replace alternator anyway - ouch expensive.
2. Both rear window regulators broke - not too expensive
3. Small oil leak where the engine meets the trans (maybe one the seal) - haven't fix it yet.
3. Vibration in reverse - maybe engine/trans mount - haven't done it yet - may not be very expensive

Other than that it's just regular maintenance and it's been driving beautifully.

Regards,
JeffreyP