I use it with many of my customers at work. It saves tons of time getting the drawings I need to do my bids at work.
My customer sends me an invite, I accept it and depending on the size of the folder, I have access to the drawings in a matter of minutes and can pick and choose which ones i download to my desktop.
I also use the phone app which allows me to send a tiny url to my email addy so I can download and work at home.
I personally love it!!!
Easier than yousendit!
Just be careful when you delete files. If the folder is shared, once you delete from the folder, then it is gone and no one else can see it.