I have a Lean 1 and used it last year for the first time. First trip was a Hunter's Island solo, and I loved it! Nice weight savings for me as I did not need to pack tarp, tent and small bug shelter. Big space, and my worries about getting wet without a sewn in floor were put to rest on that trip as it rained nearly every day and I stayed dry. Very roomy as well; plenty of space for my wife and I on my second outing with it later last summer.
The downside, for me, is a lack of ventilation; it can get really warm in the Lean. Also, the standard mesh screen does not keep out no-see-ums, and that was annoying. Mentioned that to Dan, and he is willing to replace the current screen with a finer mesh, but he warned me that would potentially make for an even warmer unit.