FWIW.......
I've reloaded cases from the PTR and original HK. The flute marks are cosmetic only, they do not affect the ability to reload. Neither does the small dent made by ejection. The problem with reloading is that the G3 style rifle flings the brass about 1/4 mile.
As far as pickiness with ammo, my PTR does not seem to display this at all. Most people have difficulty feeding ammo because they do not get the chamber properly cleaned. All dealyed blowback designs are what my friends and I refer to as pigs.....they eat where they $&!^. This can be remedied by purchasing the proper chamber brush.
What turns most people off of the G3 is the ergonomic set. You can not simply expect it to operate as an FAL, M1A, or AR. If you want to make the G3 work for you, you must learn to use it. The charging handle is on the left, there is no bolt hold open after the last round, there is more perceptible recoil, and the trigger is heavy, (around 11 lbs.) The gun itself is not light, weighing in around 10 lbs.
The trade off is that you don't have to take your eyes away from the sights to reload, the chamber is closed when the last round ejects, it is ammo insensitive (no tuning the gas system), it can take a 30 foot drop and the trigger will not be tripped by the impact, you can beat it on a tree, run over it with a tracked vehicle, and still fire the thing. It also has fewer moving parts and field strips quickly.
All that being said, try them both and buy what you like. I love mine, but that's just me.