That will vary based on your state, I'd imagine. In SC, Hartford is good sometimes for seniors, and Progressive tends to do well - they seem to rate heavily for age? They usually suck for youthful drivers.
Look into Allied if you're talking about teen drivers with their family. If you're talking just teen drivers by themselves, your guess is as good as mine. The carriers I've dealt with tend to be inconsistent on that.
X2 on Allied. Where I'm at so far Hartford hates kids. On the older if you write hartford with AARP discount they can be good but like to bump up rate in 1st renewal. Travelers can be pretty OK. Not universally but fairly regularly.
