I just went on a 3 day/2 night uyuni tour. I splurged and went for the tour with stays at the Tayka hotel chain, because there is heat and hot water at night (solar) and I'm scared of being cold. These hotels were lovely and the beds super comfortable. I used Creative Tours, contacted them online (had to pay though a bank transfer which I did locally at their bank's branch in La Paz, can deposit money instantly with passport for ID). They were quick to respond and sorted things out with 2 days notice. The food was good enough (cooked veggies and meat, dessert), the car in good shape, it was 4 of us plus the driver. We weren't crowded or rushed. We managed to make all the usual sights and some more unusual ones as well in 3 intense days.
The drivers are all freelancers and so it is hard to know who is the driver for your upcoming trip. We had two jeeps going together on the tour, one with a very proactive English speaking guide/driver named Abel. I'd recommend him highly. He went above and beyond, explaining things, giving us quizzes, and making sure we were happy. Our other driver in the 2nd car, Gido, was a good safe driver (if quite speedy). He was nice but didn't say as much as the other guide. It was safe and we were well taken care of, but with Gido alone it wouldn't have been as informative. Gido only speaks spanish, by the way.
It seems that the cheaper/standard tours are around $300 less than the Tayka hotel version of the tour. The difference is- no heating, dorm room shared with 6 people, they squeeze 6 people into a jeep and put the bags on the roof, and might not have room for oxygen tank (which can be important at 4950 meters, as a back up if you feel bad from the altitude).
I'm really glad I paid the extra amount for the Takya hotels, which are also a community-owned project. Each room has two large beds and an en suite bathroom. The comfort and hot water was great, as was good food- but also we saw some very secluded spots with no other tours around and it was much more special than the parts where we were surrounded by other cars. I'd go with Creative tours, and request Abel if you don't mind paying extra for an English speaking guide. You;d also be in fine hands with Gido, just a different experience.
I also highly recommend the 3 day trip. 2 days sounds like a waste, the added value on the one day is minimal before you turn around and go home. I found the 1st day the least exciting (the Salar de Uyuni) of the 3, though still lovely, so if you can make 3 days happen I'd suggest it for the amazing landscape of the Avaroa park.
