I've been using the Pnuma heated vest off and on for a few years, but I've always used it as more of a backup.
Last night I decided to try to rely more on the heated vest and go relatively light. Up top I decided to wear a FL quarter zip base and then only vests - the Pnuma heated, FL Brooks and FL Sawtooth. It seemed to work out really well (plenty of pockets in the Sawtooth, and good freedom of movement), so I will probably take the plunge on the Pnuma pants. (Man, the price has gone up pretty significantly on their heated stuff.) Part of my hesitation is due to the amount I've spent on merino wool, but I know they aren't mutually exclusive.