I personally prefer the e86 to the e36/8 clownshoe in terms of looks. The Shoe is an acquired taste.
But with the Roadsters, to me the e36/7 is classic, the lines and proportions. It's like a modern German AC Cobra, and I am not the first to make that comparison.
The e85 Z4, I just don't think it has or will age as well. Hemmings and others called the e36/7/8 Ms future collectibles...I don't know how well the Z4 will age 10-29-30 years from now.
'98 M Roadster S/C @11-16ps
'06 Saab 9-5 wagon 5mt Aero+ Tuned