In a comment to the 1 Session per VM: Another Scaling Alternative post, Ken Treis shared the following:

This particular application started life as a LAMP app, then became a Rails app, then a Seaside+GLORP app… and now it’s in GLASS. It’s much, much faster than any of its predecessors (some pages that used to take 10+ seconds to generate come up in about 100 ms), and users have already commented on how much more responsive it is.