My response is far too late to be helpful to the OP, but I wanted to chime in anyway.
For the last 5 months, I have been relocating/resizing offices and conference rooms in an occupied building. We've installed about 1500 sheets that have all been very close to customers/employees working in the building. Dust collection was a must. We didn't have any ceilings to deal with, but all the walls have been 10 feet high.
The only thing that ever stopped me from getting a Planex in the past was the price tag. When I started this job and saw that Festool came out with the Easy version, I bought one. I did NOT buy the AC extractor. I wanted to see what using my CT26 with a bag would be like before I spent the money on another vac that I don't need. We've been using the Planex easy almost daily now for the last 4 months and everyone loves it. After about 1500 sheets, I've gone through about 5 bags for the CT26. The bag keeps the dust from getting to the filter and all is great. I see no reason at all for me to put out the money for the AC extractor.
The easy reaches the top of a 10 foot wall with no problem whatsoever. The only ceiling work I've done is a few soffets that have been anywhere from 8 to 10 feet high. I am 6'-1" and I can reach 10 feet with ease. Closets and other tight spaces really haven't been much of an issue for us. Sure, the sander feels bulky when you're trying to cram it and you're 200+ pound frame into a closet, but its all technique and you get used to it very quickly. You just have to learn to choke up on the arm a bit from time to time. We have excellent tapers working with us so the amount of dust we are creating is not enormous, but it would be a major issue if we were just using pole sanders.
On new drywall, we've found that the best combination for us has been: 320 grit, the planex speed set at number 2, and the CT26 suction turned up all the way. Not all of the dust is collected though. What happens is that a small amount of the heaviest dust escapes and falls straight down to the floor. The fine dust is pretty much captured 100% and nothing goes into the air. The little bit that falls to the floor is picked up with one swipe of a crevice tool and its all good.
Keep the sander out of the hands of the gung ho apprentices or you'll find that you'll be going back to do a 4th coat on many of your walls. You can sand too far if you're not paying attention and the sander will really dig into the wall if you don't keep it flat to the wall. Other than that, it has been an outstanding tool purchase for us, I couldn't be happier. We have already signed a few new contracts for other spaces based on the referrals we're getting from this job. The feedback that we're getting from the current client is that "they can't believe how clean we are."