I would probably go with the JG MP5 to be honest, I've heard about Broxa's being hit-or-miss.
Your ultimate best bet would be to save up more money and grab an MP5 made by Classic Army. They are far more durable and sexy than the two guns you are comparing, and will probably last you longer.
Guardians of Asgaard - KF25 -
Primaries: LCT AS VAL, Real Sword Type 56-2, VFC M4 CQB Mk2
Secondary: Latino heat, TM Glock 17