I saw the aeg blowback first but after your advice Charlie that it's only cosmetic and no extra feel to the realism I didn't really see the point as it's only something extra to go wrong. If I go aeg, I don't think I'd have the blowback. I found a gbb for a similar price.
http://www.zerooneairsoft.com/product_info.php?cPath=268&products_id=8296&osCsid=bd5296770e1832cdf7068553b3321e6e
Any good?