I've had my wife on a Banshee, Blaster, Yfz450 and finally settled on a Raptor 250.
She couldn't get the hang of a 2 stroke, she liked the power of the 450 but thought it was heavy and HOT on the right foot (even with riding boots), again never got going fast and often enough to get the air moving.
Settled on the 250 as it's light and has electric start, but it is very under powered for the bigger dunes.