I know people love them, but I hate mine. It's great FF, but there's too many things I hate about it RF:
-It sits so high up that I can't see around it (yes, the base has to be attached at all times.)
-I have to squeeze DD into a little gap by the door and even when she's finally in the seat, she can't adjust without hunching over because otherwise her head is on the roof. And she's only 2.5 and 36in. I can't imagine her at 43" or whatever the RF height limit is trying to get in there.
-Getting it ready to install (attaching the base, anti-rebound bar + locking pins, removing the seat cover to access LATCH/lock offs, etc) was hideous. It took me AND my father at least 30 min, and that was after I watched the videos, read the manual, and researched all the tips and tricks.
Things I liked RF:
-Leg room was pretty good.
-Rebound control.
-Headrest area is designed so it doesn't usually contact the front seat.
That's it. I was never a big Radian fan, but I would take them over the Foonf any day of the week. It literally spent 10 minutes in my car RF before I turned around and took it out.
We've had the Britax convertibles as well, and they're so superior to the Foonf in ease of use, IMO. I also never slammed my kid's head into the door or roof in them. I have a Prius, which really is not a small car, but maybe I'd feel differently if I drove a minivan.
HTH. I honestly love it as a FF seat, but man, I just feel like they took a step forward with the 50lb limit and two giant steps back with how high it sits and all the extra pieces.
ETA- attached pic.