Flew in an out in a 36 hr period for an interview. Arrived at 1045 am on a Thursday, flew out at 320 pm on a Friday so I can't comment on how rush hour and high traffic hours at CLE are. Not really much options in terms of food, but there are a few places. Don't ask about the construction in B terminal but it seems like it has been going on awhile and they weren't actually doing anything while I was here.
In terms of rental cars, not all that clear where to pick up the shuttle to get them. Just be aware that one shuttle takes you to the rental car pick up plaza that houses Enterprise, National, etc