I am looking for an older SUV with around 80k and no older than early 2000s.
I really like the Acura MDX, Nissan Pathfinder, Lexus RX300 series. On Cars.com and autotrader, they run around the same price with these stats.

Which is the best?

I had a 2003 Acura MDX Touring, and traded it in for a 2006 Lexus RX400h. I went for the hybrid version to save gas and am happy with my choice. Honda was difficult to deal with, and I complained about some obvious problems for 44,000 miles and the dealer "couldn't replicate the problem" so they never ever fixed it. I gave up after that and worrying about rampant Honda transmission disasters. Here are some pluses and minuses to consider.

MDX:
Pro-- Sporty Handling, comfortable for most people
Con-- Legendary transmission problems, dealer service is spotty, Bose sucks

Pathfinder:
Pro-- Best of the three if you actually go off-road
Con--Rougher, more truck-like street ride, limted room for tall people

RX:
Pro-- Most luxurious ride of the three, comfort, superb reliability
Con-- Not as sporty as the other two

All three are nice in their own way. Good luck with whichever you decide to purchase!