We have a Regent, and we love it! We got it when our oldest was almost 5. He is now 7.5 and just moved to a high back booster at his request, and my now 4yr old is in the Regent. Its a big seat, and it takes some getting used to install, but you can't beat the price its at right now ,and the length of time you can use it.
I have a Ford Freestar with a bench middle seat, and I had our Regent and the Britax Marathon side by side with no problems at all. RIght now the Regent is sitting next to a Sunshine Kids Monterey high back booster (which is a pretty wide booster) with no problems at all.
Its a GREAT car seat, you can't beat the price its at right now. If you are looking at it, I would suggest buying it. You own't regret it!