I've been reading too many threads, sites, and reviews to think about this straight

DD2 needs to move to a RF convertible seat like yesterday. For DD1 we got a Diono Radian RXT and at a petite 7yrs she is STILL in it FF. Since they no longer sell the same model, I'm torn between the Diono Radian 3RX and the Graco SlimFit.

We've had such a great experience with the Diono - it's a tank (pros and cons there itself) but has such a long lifespan. However, DH has a Honda Fit and he is the primary driver so while that car is surprisingly roomy I am still concerned about the space. The SlimFit seems smaller and I like the flip out cup holders and additional supports.

Both seem narrow enough to still fit a third booster for when DD1 has friends ride along with us (whenever that happens again).

Anyone have experience with the newer Diono 3RX and/or the SlimFit to share?