I personally would rather not go through GL, ever. I'd rather find a vehicle for sale privately (which is what I did) so I can poke around with it, test drive it, etc. to my satisfaction, and negotiate normally. For some reason, the GL sales have been ridiculously pricey lately.
There are a lot of differences between the 1008 and 1009, IMO the most important of which is the gearing. The 1008's 4.56 gears are awesome stump-pullers that can pretty near climb trees, but are really, really crappy on the highway. The 1009's 3.08s are awesome for the highway, but crappy for pulling/hauling/etc., at least compared to the 4.56s.
Next most important is are the axles. I forget what the front axle in the 1009 is, but the rear is a pretty light-duty (10 bolt?) unit with a GM gov-bomb unit, whereas the 1008 has the 10.5" 14-bolt with a Detroit Locker rear (front axle in the 1008 is a Dana 60).
After that, the physical size and attributes of the vehicles come into play. The Blazers, with a rear seat and shorter wheelbase, are easier to park, and more usable day to day. The trucks are good for work duties, not so much for daily driving duty (this comes from somebody who has been daily driving a 1008 for several months now).
As for the 24v system, it's not really a 24v system. It's a 12v system that's tweaked a little bit to have a 24v starting system and jumper hookup. The isolated ground alternators can be a royal pain sometimes, same with the starter if it goes.
The trucks are pretty easy to work on (most of the time, but changing a water pump sucks), and parts are pretty cheap and readily available at any auto parts store (well, except for the few specialty parts), but they can be a bit needy if you're putting a lot of miles on them. After all, they're 20+ year old vehicles that didn't exactly get easy highway miles from their previous owners. I needed to put glow plugs and a water pump in mine toward the end of the summer, I popped an alternator last week, fried a starter relay a while back, I've got some sort of intermittent fuel delivery problem on startup, and it just developed one hell of a vibration with certain combination of speed/throttle. Oh, and in the fall I had an alternator decide to arc to the fuel hard line, burn a hole through it, and cause the engine bay to catch fire. That was fun.
Mine will soon (as soon as I can locate a real car) be retired from daily driving usage. It's a great off road truck. It's a great work truck. But, it's pretty useless on the highway, in some tighter parking lots it's a PITA to park, it's loud, and it's just all in all not a great daily driver. No way in hell I'll ever part with it, but no way I'd have it as an only vehicle. Then again, the guy I bought the truck from daily drives a 1009 without major issues, but he also has a really, really expansive selection of spare parts (one or two complete parts trucks), and that makes things easier.
