Hoist
It can be kinda fun researching different choices, but it's been my experience that I start out with a vehicle in mind, look at all the alternatives, and then end up using all the info I get to justify (read "rationalize") my first choice anyway. I just bought a Cadillac Escalade, and I looked at Mercedes, BMW and even Range Rover, but I wanted to go back to the General. By the way, I couldn't be happier, and as they say, "Chevy might run bad, but they run bad longer than anything else!" I like the beefy feeling of a GM vehicle, and from that standpoint, the older Trail Blazer is probably going to give you more of that than the GMC Acadia. Having said that, the Acadia reviews far better, with a far more modern design, chassis, drivetrain and interior (the Acadia's interior looks so much like the new Escalade, it's not funny). Here's the vedict on the Trail Blazer from Edmunds (it scores a 6.8 and claims it is functional but unimpressive, and average at best):
http://www.edmunds.com/chevrolet/trailblazer/2007/ratings.html#search=open.eq..amp.p.eq.cvehicledata%23%23-1%23%23-1%7E%7Enf12%7C%7C43686576726f6c6574The same people are impressed by the Acadia, and give it a very glowing review:
http://www.edmunds.com/insideline/do/Drives/FirstDrives/articleId=118833Here is a review from Motortrend, a mag that I think says it like it sees it (again, well reviewed):
http://www.motortrend.com/roadtests/suvs/112_0702_2007_gmc_acadiaFinally, here is a Q&A about build quality, answered by a quality inspector at the GMC plant - it's an interesting perspective if maybe a little biased.
http://answers.yahoo.com/question/index?qid=20070428075658AATAEmDOn a final note, if you go the old school Trail Blazer, given that roll a modified 110 ci Harley, I think you'll wanna a V8!!!

TE SS package, which includes the 6.0 liter V8 and better suspension, brakes, etc adds about five grand to any spec TB. Here's a Motortrend review here:
http://www.motortrend.com/roadtests/suv/112_0511_bg_trailblazer/index.htmlSorry if I'm a little opinionated - you know what they say about opinions and assholes! Best of luck.