In short, it went pretty well. Sat down via Skype with Adam, Dan & Luke for the test. We'd tested the rules before, but this was a more formalized test if you will. The rules themselves seem pretty sound, and easy to use. Tier 1 of Skies of Glass seems is indeed shaping up as promised: A fast system without a lot of detail that allows the players to get going without the rules getting in the way.
Some areas of concern? Remembering to use "clicks." Clicks are basically a measure of success in the game, and using them in combat is very important. Now, it may have been all of our unfamiliarity with the new rules, but we forgot to use clicks as they happened. It's a sound concept, it'll just take some remembering on my part in the future.
My only other concern, rules-wise, is the Barter Value system. It's coming along, but there were some applications that I'm wondering how they will work when implemented.
I think the biggest problem I had with the playtest was the venue. It was my first experience playing over Skype, and I felt somewhat handicapped by it. I'm a demonstrative GM. I like using eye contact, hand gestures and the like to convey the action and personalities of my NPCs. I also use that time around the table to gauge my players reactions and get some energy back from them. In Skype, you can't get, or do those things. I felt very limited in my ability as a GM to run a good session for them. Not saying that I won't try Skype again, but it'll take some getting used to.