I have a 2004.
In 2005, they changed the rear window to a power slider.
By the end of 2005 most had updated differential covers that were finned and bigger rotors.
They also included a tailgate assist.
In 2007, updated tweaks eeked out an extra 10 hp
In 2008, there are a variety of options including gauge cluster refinement, long bed.
Of course the rule typically is the older model is cheaper than a newer one so your budget is what sets the buying point.
Want to be rare-get a 2004 Sedonna!
If you're thinking of upgrading to Stillen Brakes, then get something that already has 18" wheels.
I had an 05 and now an 07, which I like much better from a fit and finish standpoint. My 05 was still buggy with some minor annoyances that went unresolved. The 07 and 08 have a bit more grunt. The 06 is probably the better value of the older models.
Quite possibly the best year was the 08/04 in a Radiant Silver. Fastest color with the least amount of problems. Sure, you could go new, but that is o yesterday. Paid off sounds better than, "Here are your keys, 60 more payments and that bad boy is all yours". LOL
10/04 in radiant silver is a winner as well! lol. seriously tho, not a single problem ('sides the easy brake fix tsb). oh, and i had a squeaky belt so my (awesome) technician got me a new drive belt tensioner & belt free under warranty.