they look alot easier to drive on and off.
for anyone who has never tried driving up metal ramps you need balls. they are quiet steep and i've always worried about going over the edge. especially as most are made for cars with normal width tyres, so anything wide goes over either edge, and does mean the stopper on metal ones aren;t as effective.
the foam ones look alot more user friendly. especially for wider wheel setups.
shame they aren't cheaper.
good find tarmac, and good luck with sales