I think that the 2001 and 2006 are in mechanical terms the same. I would say go with the 2001, same miles and a lot cheaper. Do they have the 4cyl or v6?
No - a 2001 GV should be an SQ series chassis, a 2006 GV should be JB series - and there are significant differences in between the two.
SQ series is body-on-frame construction, part-time 4WD, independent front suspension, live rear axle - JB series is unibody/monocoque construction, full-time 4WD (more on that later), independent front & rear suspension.
Depending on the model & options available in any given country, the JB series could have either full-time 4WD or four mode 4WD, in which the four modes are full-time 4WD (center differential unlocked); high-ratio 4WD with center differential locked (same as full-time 4WD but the center differential is locked); neutral; and low-ratio 4WD with center differential locked.
The JB series is more of a soft roader, stops just short of being a crossover (Suzuki claims there is a built-in ladder frame), but typically a very nicely equipped car, and impressively strong in terms of collision strength (a guy spun an F150 in front of a friend and she T-boned him and was then hit from behind by the car following her).
The SQ series is a light truck based SUV and that shows not only in the ride, but also in the fit & finish - there is always a certain degree of movement between the separate body & frame as you go over bumps and consequently, squeaks and rattles - don't get me wrong - I drive an SQ and I love it.
If I were in your position, I'd be going with the SQ (the 2001), for the reasons that Jeff mentioned, and because I think it has more off road potential - but for a week-end run around (or for the wife) the JB is nice.
Oh - I forgot - the SQ has way less electronics than the JB, easier to diagnose, easier to repair.
