I took a punt on the Gerbings which arrived today, but I'll be sending them back for two reasons.
Firstly, they just don't fit my hand shape - finger tips pressing tightly against the ends whilst there was a half inch of excess thumb flopping about, so that was a non-starter.
Secondly, the heat was well below my expectations. I made sure I unlocked the hottest setting and attached to a 12V power supply and even after 20 mins on max, they were 'warm' at best. I inserted my pyrometer and the hottest reading I could get anywhere within the glove was 30 degrees C. Maybe that'd be enough to stop my fingers hurting from cold, but no way would that bring the 'warm and toasty' as per some of the reviews. As for the hottest setting needing to be unlocked to prevent scalding? Not a chance. Lovely gloves but the heated bit was very underwhelming.
On reflection, I canl't be faffed with cables and connections, so will just buy the warmest Aplinestars (they fit my hand shape) I can find - not that their website indicates which are the the warmest.