I like it, it looks like two different guns though. Look at the ejection port. The one with the hopper adaptor looks like one solid piece, no spring. The other appears similar to an AR ejection port with the spring present.
I'm also not a fan at all of that bottomline, depending on how they execute it that will interfere with being able to use other AR series grips.
Overall, it looks promising though.
Team Trigger Happy