I have both and like them both
I have 3 Gen 4s all 2006 year model
SR5 4.0L 4x4
Limited 4.0L 4x4
Limited 4.7L 2WD
I have to admit the responsiveness to the pedal of the V8 is very nice and on the Interstate it just slips down the road so smoothly! It also has a nice throaty rumble if you get in it, but my daily driver is the 4.0L Limited. Basically stock except for Bilstein 5100’s with front raised the full amount. I switched in the Bilstein rear springs and the result is a nice level vehicle with almost a 3” lift. It’s not so noticeable except when I swing my feet out and I have to slide off the seat to touch the ground. (And if I park beside a bone stock T4R). It has plenty of “get up and go” but it does take noticeably more pedal to get it going than the V8.
I have never had the pleasure of driving a V8 4x4 and not sure if I’d like losing my 2WD option.
At the end of the day they are both such great reliable engines you can’t go wrong.
BTW, the V6s have 200k and 265K miles and the V8 just hit 301K. (It had a timing belt at 180K but that’s it).