I really like the new system. Keeping I-95 along the Maine Tpk route solves a lot of weirdnesses in driving directions, as does getting rid of any number whatsoever for the "Falmouth Spur" (which is where 95 and 495 used to split, 95 arcing down to meet back with 295). I remember going to the "wrong" exit for LL Bean because I was on 495 instead of 95, because I didn't realize I had to exit the turnpike to stay on 95. Talk about a *long* distance out of the way!
I also like the mileage-based exits up there. It's great to know that my next exit is 47 miles away just by knowing the next exit number. It makes planning those gas station visits much easier.
If you stop at the first visitor center / rest area in Maine, they have these very well-done brochures about the renumbering, talking about and showing the new layout on a map.