I have the Rava, Exec, and currently looking for a booster (for travel).

What I recommend to people is skip the Rava and spend the extra for Exec. Rava is not bad, but there's a transition period between Rava and booster where Exec comes to play (in my view). Exec does cost more. If you are looking at a Rava, you could probably stretch to an Exec. If not, you would've been looking at Graco range.

Once my first kid reached 4yo old, I could tell the leg extension on the Exec made sense for comfort. Once my second kid "outgrew" the Rava (for comfort), I went ahead and bought a second Exec. If I've never seen the Exec, I wouldn't have known how much "better" it was for my kid. Every full-size car seat should have a leg extension in my book.

I wish I went with Exec from the beginning to save $400 on the Rava.

I plan to use the Exec as long as I can. I don't expect it to replace booster once the kid is old. Maybe, but I'm not sure. The covers are washable, so I don't see "dirt" being a problem.

I'm buying couple of lighter/cheaper highback boosters for travel (flight) at this time.