I had a Priori and loved it. I wish the shell was a little taller so my DS could RF in it for a little longer, but other than that it was a great seat. The shell is taller than the Roundabout, but my DS has a long torso and he outgrew it RFing by 2yrs old. I think the seat padding is better than the Britax, it reminded me of the squishy pillows you used to find in Walmart.The belt holders are way better to, they hook on the side of the seat instead of velcro. It fits in most small compact cars. It can recline in 4 different positions FFing without needing to unbuckle it. It has a wide base so it was easy for me to buckle into my Mazda Protege.
I sold mine and bought a Roundabout 50 to keep my DS Rfing as long as possible and I'm really not feeling the Britax love.
I would buy it again if i had another baby. I think a lot of people don't look at it because the FFing weight limit is only 40lbs, but I wasn't worried about that because I have a Regent my DS will grow into once he's FFing.