1clicc...
If you have other lowers already and just want a MEGA for fun, go for it....
...BUT: if you don't have any lowers, please don't wait for a specific brand to become available - grab ANY legal off-list lower you can while you can. They are all good, functionally equivalent, well-made, and can all build an accurate, 100% functional rifle.
Don't waste valuable time being picky - the clock is ticking and the hammer could fall anytime.
Bill Wiese
San Jose CA