Crossfire was essentially the R170 SLK320, the V6 vs. the SLK230 which was the supercharged 4. At the time, the V6 was considered more of the tourer, vs the boosted 4 which was sportier...I've owned both and preferred the V6, but both were great cars. They were not considered as sporty as their direct competitors at the time (Boxster, Z3), but by today's standard I'd definitely consider an R170 a sports car, and they can be had with a manual which is an oddity for Benz.
The Benz interior is pretty nice IMO, but suffers from the peeling paint issues on the console and other areas, which really looks terrible and caused a lot of people to assume the whole interior was cheap...Really, the Benz materials and layout are very nice, and it's aged well. The paint peel is a cheap/easy fix (reference my SLK230 S&S thread).
The Crossfire interior is the same layout, but uses way more grey hard plastic from the Chrysler bin.
Between the two I am not sure why anyone would choose a Crossfire over the Benz version, unless you get a real screaming deal on the Crossfire.
