Hmmm, I run a h5 and it's a kickass motor in mine and yes it does need some maintenance.
On the h5 there are Banana options. To be true, get a gel cell 12v like on motorbikes if you can afford the weight penalty or Lipo it. It's a simple mod to add 12v.
The key to the H6 is it uses a RELAY... Which in theory is a great idea, I hate the sparks on my H5 of raw contacts.If the build was crap, then that'd be a different story but it's not the norm. TM has a better history in RC accessories than they do their cars..
Personally I'd avoid the dual 540 and get a H5... and better still get a mugen or hudy