The 4-Runners are pretty expensive and the RAV4s are pretty small, so the Highlander kind of falls into the middle.
We rented a Highlander for the 10 days that we were in YNP/GTNP from Dollar in Jackson and it was great on the road. Plenty of room for 4 and our luggage, plus great gas mileage. The rear seat had more foot/leg room than my daily driver 2005 Mountaineer or my Wife's 2004 Grand Cherokee. I don't mind AWD, but prefer that they have a low-range option, which the Highlander and Mountaineer don't, but the GCs do.
JEff
