We've been through three different ones so far, and LO screeches, arches his back, etc. as though he's horribly uncomfortable (it's definitely the car seat... he doesn't have reflux or anything). When I've felt the interior of them, you can feel hard plastic, so no wonder he hates them. (He liked his infant car seat, a Britax, until he outgrew it, so it's not a car thing or a RF thing.)
Does anyone have one that's super-comfy for LO, not just safe? My parents and IL's live hundreds of miles away, so we need to invest in something that my baby will like for long trips.