The best rate I got was from Hertz - intermediate SUV at USD 240+ per weeek before LWD but not sure if I'll actually get a 4WD. Dollar offers a Standard SUV at a hundred dollars more and I have that on reserve.
National's rates on the internet was rather high.
Be careful you don't run into a no-show/cancellation fee with either company if you choose one and cancel the other. I read through the T&C's for both Hertz and Dollar and I didn't see anything. Thrifty has a 24 hour cancellation deadline to avoud a one day charge. Their rate is smack in the middle, $299/wk for a Liberty or similar. I've never seen a Dollar or Thrifty SUV without 4WD, but my experience is Canadian. I can't speak for Hertz but they generally carry higher up models so it should include 4WD. Hope this helps!