Need I be concerned with magazine selection?

Tapco. $11.95 for new, formerly LEO magazines.

Out of stock, expecting a shipment in Feb of 2005 :(

USGI is definitely the way to go. External condition doesn't really matter; just make sure the feedlips are in decent condition.

An insanely good upgrade, though, is magpul followers. I wrote up a little review on my website, for anyone bored enough: http://top-quark.com/cgi-bin/blosxom...gpul.writeback

The HK mag is amazing. Every other mag feels like a toy compared to it.