I pulled the trigger on one of these a few weeks ago, and have just finished my first ferment cycle with one. The short story is that it works great and is a pretty good value.
I did a lot of reading on this thing before using it and there's a long thread on HBT that documents a lot of best practices and problems people ran into. One of the main concerns for people is that the lid doesn't seal, but mine didn't have a problem. I used teflon tape on the threaded connections, performed a leak test and cleaned and sanitized.
The common suggestion was to wait 12 hours for the kettle cold break to settle into the ball, dump that and then pitch. I decided to follow this advice, but I may not do this in the future due to the preference of having yeast working as quick as possible to defend against infection.
The unit on the stand fit perfectly into my keezer (with collar). I used a blowoff as the airlock was too high for the lid to close. This fermentation was done quite quickly, it was within two points after 3.5 days. At this point, I wanted to harvest the yeast but couldn't get at the ball when it was in the keezer as it was awkward. So I pulled the fermenter out at this point and left it out. I do this with most of fermentations anyway, as my Keezer does double duty serving and controlling fermentation temps. I usually do 4-5 days in the keezer, then 7-10 days at room temp.
I've got pictures below of the yeast just before my first harvest. I shut the valve off and let it settle for a couple hours and you can see where the yeast started to settle above the valve. You can also see where the yeast in the ball continued to ferment, so when I disconnected I had a bit of a mess. Overall, I got a mason jar about 3/4 full of slurry. I use a hop spider so this yeast looks pretty clean.
When I reconnected the ball and opened the valve, the yeast was very slow to go back into the collection ball, but it eventually all did after a couple hours. At one point I thought I could just open the valve and dump the trub into a bucket, but now I can see that it wouldn't work and I'd likely lose a lot of beer.
On keg day, I lifted this rig onto the counter top to get some height. Side note- this rig is awkward, the straps they sell make it manageable. To keg, all you have to do is remove the collection ball, and attach a hose attachment and let it rip. This thing drained into the keg in about 60 seconds. I'm slightly concerned with how fast that went and potential splashing that could lead to oxidation. I will slow it down on the next try.
Anyway, like I said I'm happy with this and think it's a great value. Let me know if you have any questions!