OK once I get my lower done, I have been thinking I will also make an order of 30rnd mags in case we lose the bigger mags after the election. Sooo I was looking at a few places about mags and I was thinking I would get some bushmasters at first then I came across Magpul. Now I have waded through alot of reviews and from whet I can tell they are the best on the market. So I was wondering are they? has anyone had a bad one? and how dose the window work, I am abit leery of any mag you can see into but dose it work well?