I'm a depositor and am looking forward to the upper. The mechanism is a proven design. Eric at Lakeside has been making postie Tippmanns using the scaled Browning action for years, and knows what he is doing.
I think it'll lend itself well to customizing. I'm going to try and create a baby tripod-mounted "crew" weapon using a highly modified lower. Other guys are going to go for the SAW look.
I'm purely guessing here but based upon what I've read on the Lakeside message board, and what Eric has mentioned, I bet we'll see the first batch delivered by October. If it takes longer, that's fine by me because lakeside communicates with their customer base, unlike an unnamed but heavily advertised upper with a name similar to "Shrek".
.22LR FA is just plain fun, not only because of the cheapness of the rounds. The ROF is high, basically no blast, easily suppressed. Chicks dig 'em too.