Hell yeah! I LOVE driving my E430.
As per your list:
Rust - Definitely a factor up here, but if you find one well-maintained, it will last.
Cracked dashboards. - mostly all have this, but I have seen members get create fixing it (epoxy and paint, etc)
MAS sensors. - no problems yet
catalyst replacements - yes, these do go (start to rattle). OEM expensive to replace ($800-1000 each by all acounts). There have been reports of successful replacement with Magnaflow SS cats, only $200-300 each, still pass emissions.
leaky steering racks - no problems yet, don't think it is a big issue
spring perches. - mine was checked at the dealer under a tech bulletin - no charge. they were fine.
creaky seat frames. - again, can usually be fixed without replacing.
leaky diffs. - no problems yet.
broken sway bar links. - don't think this is a big problem either, can't comment. My car has the E55 suspension, which is beefed up a fair bit, may not be as big an issue.
crank shaft position sensors. - can't comment
think paint.?
m112s that eat oil - my M113 consumes a bit of oil, but since the last change, it has used about 1.25L in almost 5,000 Km. Nothing to worry about.
606's that leak fuel/weld themselves to glow plugs - can't comment
RUST -
Other issues are rusting on the door frame, around the weather seal that surrounds the window. There is a recall for this as well. I think it only affects earlier models.
It seems like sometimes we get attached to a chassis and grow to love it and memory is sometimes selective about problems. I loved my 300E and it served me incredibly well. Was a hard decision to go from the W124 to the W210. However, I absolutely do not regret it.
Remember the W124 issues? M103 oil gasket/head leak, AC evap anyone?
, breaking sunroof lifters, horrible stock headlights (making the $$$ euro upgrade a virtual necessity), horrid stock radio, etc.
My E430 is an absolute joy to drive. Looking back, the 300E was...well it's almost not fair to compare, really. The 5-speed tranny is night and day to the old 4-speed. Power? Not even a contest. The E320 is a great performer on its own, with incredible gas mileage and the E430 is just fun, fun, fun. Considering the substantial increase in output and torque, the M113 doesn't consume much more gas at all, esp. when driven conservatively, which is an impressive feat.
Mine has 140,000 Km on it, going strong. When I had it emissions tested a few months ago when I bought it, it scored perfect 0's. Nothing came up. I asked the guy if it was an error, he laughed and said no, just a clean-running engine.
One of my techs has an early W210 E320 with high mileage. He loves it. No rust either, he washes it frequently in the winter.
Like POS said, look around, you have the knowledge and can find a well-maintained car in excellent shape for cheap! It's kinda sad how cheap they are, so even if you factor in some major repairs, you are driving one hell of a car for peanuts! Did you see the beauty suginami just picked up?
So...yeah...you could say I am 'happy' with my 210.