I have owned this mini van since it was new. I am currently considering a new vehicle. I am researching the same car. This car has done everything I have asked of it and then some. It is an extremely versitile vehicle, from hauling 7 people to piles of lumber with seats removed. This car has never left me stranded and the only reason I am considering a new one is mileage.
We've owned several vans over the years and use them pretty hard in our antiques business. The Lumina is far superior to the Caravan we had (I'd not own one of those again if it was gifted to me - BAD experience). The Lumina is right up there with our old VW Vanagon, but much more stylish and, yes, has power to go up hills and air conditioning! We like this vehicle, have friends who own them and would recommend it as a good mini van option for someone considering purchase. We bought ours as a lease-return with 25K on it and it is now at 80K .. mostly all trouble free.
My van had 60k when bought in 98'. In the last four years I have put an additional 51k. It still has lots of power and gets 25 miles/gal highway. Just bought 2001 dodge grand caravan. It gets 21 highway and similar power.