Up until recently, the MakerBot I've been using had an acrylic build platform covered with blue painter's tape. I print PLA parts at 230 C, and prying the finished parts off was a real struggle, even with a putty knife. They have now replaced the build platform with aluminum covered with painter's tape and getting the parts of is much easier. I guess it must have something to do with the aluminum conducting heat away from the surface fairly quickly?
Chuck
