||I would stay away from these. I have two and have had problems with both of them. For the first one, I had it for about one month before one of the cells died, so now it can't hold a charge and is therefore unusable (and dangerous, too). For the second one, I also had it for about a month before it melted my gun's Tamiya connector, so now they're fused together.
High rate of fire
Wiring seems solid
Small and compact
Short battery life (if you shoot a lot during games, this won't last very long)
I had problems with mine, so reliability is iffy
Neither lasted more than a month for me
Rating: [2 of 5 Stars!]