Change of Opinion
Allow me to recall my opinion from November, when i said my Berg 570 would be the ticket. It's vastly superior to the 300 XCW I ran, but here are a few tidbits I've learned over this winter.
Close ratio tranny -not wide ratio - is better on a snow bike. Because you're not rolling wheels and it's easier to stay in the power and not bog when upshifting. The track just robs too much power for wide ratio trannies, even only torque happy 570.
Motocross bikes and 2 strokes make quicker power, the enduro bikes power band is not actually ideal for snow bike. Think about how you're almost always wide open on the snow because gear ratio is already cut in about half. Grabbing max power quickly and comfortably staying there is easier with MX motor.
Motocross bikes - like SXF and KXF come stock with stiffer front suspension, probably saving you the money of upgrading an enduro bike - which you absolutely must do to keep ride height up and prevent nosing into everything.
Motocross bikes are cheaper and I couldn't care less about the plate. If you care about a plate, then this question answers itself and maybe you'll want an enduro.
Weight does matter on a snow bike. The lighter and lower you can get the weight, the better off you are. Motocross bikes have an advantage here too. If you haven't ridden the new KTM 450 design you won't believe the magic they worked. My '08 450 XCW was pig that wouldn't turn no matter the setup - KTM knew it too. That's what drove me back to 2 stroke 300 for tight woods riding.
Basically…it's not just the displacement and torque…how/where the power is made is more important imho and multi-bike experience. I miss how fast my 300 made power, but that bike clearly needed more of it. I'm probably selling my Berg 570 and getting a '13 or '14 KTM 450 SX-F for my aggressive riding style.
Good luck.