I had the DP blower, and I currently have the Sidekick and Master Blaster (w/30' hose). I didn't have any luck with the DP blower. The motor actually burned out in the first 5 minutes of use, so I ended up returning it and getting the Sidekick instead. Even when I did use the DP blower, it just felt really awkward to carry around. I was always afraid I was going to bump it into the car.
I was quite impressed with the Sidekick (much moreso than the DP). It's really great on wheels and trim areas, but it's too small to do a whole car. The only downside is getting out extension cords and putting them away. I just recently got the Master Blaster. I've only used it once so far and I liked it quite a bit. As previously mentioned, the hose is really stiff (I'm currently searching for replacement options), but it is powerful enough to do a whole car. I have it mounted on the wall with the hose rack, so it's more convenient to get out than the Sidekick. I will say that I can dry a car faster with towels, but knowing that I can't introduce any marring is a big enough benefit to make it worth it.