I just went through a similar thought process and decided on the PS90. I'd like a Sig 556 but have been reading that many of the top rails were not attached straight and are going back for repairs. I decided to wait until it was on the market a bit longer to work the bugs out of it. I figured the PS90 has been around awhile so was able to research it a bit more. I also considered using my refund for ammo, mags etc. but figured I can pick up that stuff when I have smaller amounts of extra cash; it's not often I get a lump of money that I can buy a PS90.