If "I" were to buy one I'd try finding a 98 or 99 in need of lots of work
that I could pick up cheap.
OTOH, the 2000's were alot more refined, and came with the maintenance commitment plan, which means they should have had the sythetic oil virtually since day 1.
The 98-99's have a normal looking radio, starting n 2000 they have the large "MCS" radio. I find the 2000-2001 MCS a little annoying at night, so be aware of this if you drive in darkness alot, may want to see what it's like first. In 2002 they went to a gray screen, alot nicer at night than the blue screen. But if you buy a ML320 you can add the nav system to the MCS unit, the V8's I believe may have all came with Nav from the factory.
I also like the look of the 2000 and newer with the body colored bumpers and mirrors.
Gilly