After reading about PEI being the "ultimate print surface", I decided to join on the band wagon and give it a try; I was not disappointed. The bed adhesion is awesome with both PLA and ABS. The biggest problem I have was with sticking the PEI to the glass build plate. I ended up using a mix of double sided tape and blue tape (both 3M brand). In the future I would probably go with a thinner sheet of PEI to negate the affects of thermal expansion as the heated bed does its thing. Links to the tape and PEI: PEI and 3M tape
Also, here is a great post about sourcing, installing, and using PEI: post
Also, here is a great post about sourcing, installing, and using PEI: post