Thanks!
YES! I'm much happier with the Flip-pac. Truth is, except for the quality (read: thick tent fabric) and how comfortable I was on its mattress, I ended up hating the RTT. I was at a point that I probably would've been happier with a quality ground tent, but even that wouldn't fix my situation with the dogs. I needed to switch to something that would allow me to take them with me, and they're not small. The Flip-pac provides enclosed shelter for them and quick and easy set-up/pack-up.
I still haven't established what kind of hit I've taken with my gas mileage yet. I would guess 1-2 mpg. I was seeing just over 17 MPG on the highway fully loaded with the RTT and 4.88's (70-75 mph) You'll need to look at changing your driving habits if you're one of those people that stress out about seeing their engine sit around or over 3000 rpm. The 3RZ will happily buzz along all day without complaint.
Don't forget that you wouldn't be losing the changing room area with a Flip-pac. It will just migrate into your bed. Add a couple of windoors and the easy access to your bed won't really be lost either.