Are these worth buying? I just wondered if I should stay with the steel mags. Has anyone had theirs crack or melt?

The Bulgarian polymer mags are the best available for the AK; if you can find them.  I would be more worried about the steel mags rusting than the polymer mags melting.

Not to hijack your thread, but does anyone know whether or not JOEKEN received the shipment of polymer/bakelite mags.  I'm on the list, but I haven't heard anything.

The Bulgarian mags seem to fit into the mag well a little smother. They are a bit lighter too, but not that you would notice on a fuly loaded rifle.

I have over 100 steel mags, and 75 polymer mags.  I have had 1 of each go bad.All the heat generated by the rifle is well forward of the mag. well so heat build up should not be an issue. If it is, the hand guards would be to hot to hold before you got to that point.

Poly and bakelight AK mags are real tough. Now some AR mags may have given you cause for concern. Some Izzy Orlites have brittle feedlips from desert FA use. And Canadian Thermolds did not have the Zytel fiber stuff in them that the US mfg had, so they became Thermelts. No problems with US Thermolds in my AR either (can't bend the feedlips :)