What year?
I'm going to operate under the assumption that you're talking about the 190D 2.2 or 2.5 from '84 to '89...there was also a 190D car made in the early '60's, but these are rather rare these days.
It's fundamentally a good car...keep in mind that both the 2.2l and 2.5l engines have aluminum heads, so be careful not to overheat it...although head warping isn't as big of an issue with these two engines as it is with the 3.0l 6 cylinder found in the '87 300D. I'm not aware of any chassis-specific issues...the biggest thing is to make sure that the suspension is in decent shape. Suspension issues on an M-B can get very expensive VERY quickly, and often result in premature tire wear.
I haven't dealt specifically with a 190D, but one thing I've learned is that, if you want a vehicle that gets you from Point A to Point B, and you're short on $$ but are mechanically inclined, an M-B diesel can't be beat. However, at the same time, if you want a vehicle where every last little thing works flawlessly...it's possible to do with am M-B, but it's going to get expensive very quickly...for example, you can expect the cruise control to not work and to cost about $400 to repair if you want it to work. The climate control can also be iffy, although it may have been better-maintained in a Florida car. If you can find a car with manual climate controls, that would be better, although I'm not sure a 190D U.S. variant was offered with manual controls, and finding a Euro gray-market car isn't all that easy.
Hope this helps a bit...good luck!!