Building a budget AR?

Are you building a budget AR?  I sold my DPMS and would love another AR so I'm thinking of starting a new project.

"Operation: Budget AR"

There is no time frame involved so it really comes down to just waiting for good deals.

Part one is the lower receiver.  Guess how much I found it for?

$50!

Granted, it's not a brand that most of us have heard of but I'm thinking abou it.  What are your thoughts on SI Defense?

SI Defense $50 Lower Receiver: SI Defense

Thanks to EveryDay, No Days Off for the find.