We have had both Proform and CSR on my car. The Proform performed better than the CSR and was much more affordable. The CSR works fine, was more money but looks GREAT (polished aluminum) with the combo that we have. So it depends on what you are wanting.
i have a csr,which when i bought it was csi.i had it for four years before i had a failure.they replaced the motor for 100.00,now since then ive had 3 motors replaced under warranty in the last 2 years.1 of them cost me 2000.00 race when it failed during a true street crusie at which i was #1 qualifier by half a sec. so now i keep a spare motor for it in my trailer. we've got a proform on our street car and had no problems out of it!!