i don't think there is anything wrong with the c-prod made mags. hell even the 30 round 7.62x39 mags seem to work like clockwork for me. i just spent 6 full 30s of 7.62's the other day not a hiccup.
since the weekend is close i would hold off till CDNN puts up their weekend/holiday sale.
i have been getting a lot of mag deals from them lately.
as far as what brand of mag to get D&H, DSG gi mags, c-products, and the mag-pull P-mag are top bang for buck picks.
last time i was over at copes they had the D&H mag with the no-tilts for $9.99 IRRC not bad.
fusil and lancer also make good mags i have been told.
if you shop around you could find some deals.
copes, CTD, aim surplus, bravo co usa, midway USA,44mag.com ,palmetto state armory, are all top places to shop for good mags cheap.
the best prices i have seen were the $5 DSG mags from CTD, the $6.99 C-prod mags from CDNN and the $9.99 7.62x39 mags from palmetto --though these are "blowout prices"
i would expect to pay around $10 for a good 5.56 mag generally speaking.
i rally like the magpull-p mag but it is rarely on sale for less than $14. that will buy two of the on sale C-s or nearly three of the on sale DSG's--LOL yea i am CHEAP--LOL