I have several 650s and the 665 appears to be a newer version with the ability to control more devices.

Things I dislike about the 650s - buttons are "wearing out" (some need tinfoil or conductive paint on the back to work), also if you drop it the batteries lose contact and it reboots.

Would a 665 be an improvement or is it pretty much the same? Thinking of buying one now that they're cheap rather than refurbing my 650s in some cases for the third time.