What’s the best ?
?
You are talking motorcycle gear, 12 volt DC?
overdriven XM-L2, heats up fast 
No lol I was talking about something like this
I wonder how good are they and if they would give you reasonable protection from absurd cold like we are having now in the northern states for running errands inside the city.
The 12v heated clothing that has been around for 30+ years for motorcycles is very useful (jackets, vests, neckwarmers, socks, gloves, etc) but you are tethered to within about 2’ of your vehicle w the power umbilical cord.
This Bosch system sounds neat, still has to be a system of little wires…so well proven.
Reviews say they are good. I’ve talked to some people with the Milwaukee ones and they said the jackets are very good.