44mag.com and Botach have both served me well. No problem for me with Botach but I have heard the stories. Their prices are usually pretty low.
DSG Arms is where I get my Pmags (With the JBT discount they're only $11 for non-window version)...For Glock mags I wait until CDNN has a sale on them.
I've orderd from Botach half a dozen times. The last one was such a pain that I'll never deal with them again.
What discount is that and how do i get it?! Does it work for 20 rounders?
I've used CDNN with good results in the past.