Gerbing products are well worth the money, as being warm and avoiding frostbite is actually priceless.
My wife had always had problems with keeping her hands warm no matter what I did for her (hand guards, many gloves etc.) until I got her set up with the Gerbing Gloves, problem solved.
The Gloves work good but I now have her setup with the heated Glove Liners and they really work, and if she doesnt adjust them down, they work too good. We were up in the UP on a really cold day and a few from our group had way frozen hands (those that really hurt warming up) and my wife thought her hands were plenty warm and when when she took her gloves off actually had a couple of blisters from the heat, lesson learned, now she adjusts them down.
Now she has the heated jacket liner which she uses under her uninsulated Jacket and stays toasty warm even on the coldest of days without all the bulk of mulitple layers.
I would go with the hardwire gloves, the wiring comes with Gerbing products, but I would also invest in the temp controller.
My 2 cents...
CW