My $0.02...
I'm fortunate enough to own one of each so here's what I think.
The two cars are really not comparable...different cars created with different goals, but...
The 16V is smaller and lighter, in terms of nimble handling, feel, and 'fun factor' the 16V wins hands down. Having said that, much of the enjoyment I get from it is solely because it has a manual transmission. I've never driven a 16V with automatic but I have to imagine some of the 'sportiness' is lost.
The 500E is larger, heavier, and much faster. It handles really well but I'm always aware of the mass.
Overall, I think the 500E is a better all around car. On the street at 7/10's it's faster, corners as well or better, and V8 torque always makes me smile.
If you search this site, you'll see where a basically stock 16V was just about as fast as a 500E on the track. So, take your pick, decide what you want, and just do it!
