I had a Clarion car unit a long time ago, it was very nice, altho I played with a few Alpines, never owned one. Can't remember all the car stuff I had, had several cars with built in systems for a long time in between that were just fine, even Bose
I've been using a Kenwood head unit in my van for I think over a dozen years now altho it doesn't seem that long...it's been great, altho navigation could be more intuitive, it wasn't all that expensive and has sub pre-out as well as L/R pre-outs, I use the built in amps for the door speakers but have a power amp feeding four more in the rear as well as another amp for the sub.