Like sniper69 said on the mag numbers. I do not think one is any better than the other.
Sorta like Izzy vs Tula arsenals. Tula Mosin Nagants bring more money than Izzy Mosin Nagants while Izzy SKS's bring more money than Tula SKS's.
As for Polymer mags vs Bakelite, I can only assume the Polymer has to be better....It is newer. I doubt they would switch production to an inferior material. That being said I still have not heard of any problems with the bakelite mags. I recently picked up several AK74 bakelite mags for < $5 a piece