Those are the only real things that are a major consideration. The cruise amp also has a tendency to go bad (mine currently is).
Even though the 602 is pretty much just a shortened 603, it doesn't have the head problems the 603 does. Check the ALDA plumbing before you judge the car's power. Should do a 0-60 in about 12 seconds. If not, check the ALDA stuff. Mine was all clogged up when I got it...it did a 0-60 in about 18 seconds...approaching 240D territory
They're actually quite quick (compared to the majority of the MB diesels), and with the fantastic handling of the 124, it's a great car. Good mileage too, expect to get 30mpg regularly in the real world. Highway driving gets 32+ depending on speed. Do 60 and you'll maybe get 35-36mpg.