I've had my Atmos for about 4 years. I like the fact that it is a hybrid BC: mostly back inflate with some side. It also has excellent lift.
My only problem was where the velcro was for the hose: I found it too low to be able to fully vent the BC. However, given that there are multiple other ways to purge the air out of the BC, it is more of an inconvenience than anything.
BTW, I'm not sure if the newer versions still have this problem; as I said, mine is about 4 years old.
Meanwhile, I have had no packing/travel problems with the BC: it fits just as easily in my roller bag as it does in my little mesh boat bag, regardless of which exposure protection I am taking (wetsuit, drysuit, etc.).
Feel free to PM me if you have any other questions.
Take care,