This comes up a lot and there are so many opinions as to whether the couple extra feet in length is a problem or not.
In the end, it comes down to your intended usage and comfort zone:
IF most of your stays will be at places without a length restriction OR you are OK with the possibility that, when you do arrive at a length restricted place, you might not fit and will have to go elsewhere - Then go for it.
IF most of your stays will be at places with length restrictions OR you will worry yourself to death every time you decide to try a new place with a restriction less than your actual length (stressing about "will you fit" until you find out you do fit or then stressing because you have to find another place to stay because you don't fit) - Then you're probably better off going with a smaller rig and not enduring all that stress and worry.
Calling those parks where you know you will want to stay and asking them if you would be OK with a 37ft rig will likely help sway you on way or the other. My guess is that a campground that limits to 35ft is more likely due to the actual campground (parking pad lengths and/or campground roads) rather than the roads leading into the campground. Shorter length restrictions are often due to the roads leading into the campground, especially out here in the Sierras.