Good advice to go the few extra $$ for stainless. I even went a few bucks more and got the Creamers - very happy with them for over a year now.
I had a Perlick creamer faucet that got enough build up to not be able to shut off after about 6 months. The beer in when it stuck was imperial stout, so it was pretty thick. I believe the o-ring tore a bit when the faucet was opened, and would not seal again. I also could not get the faucet off, so ended up replacing the guts with the innards of a standard Perlick. Now it's been running fine for quite some time.
Also had the same problem with others not understanding that it does not shut off when you push it all the way in.
tldr: go with the standard style stainless Perlick faucet.