I bought a capstan winch last year, and after having used it several times, I'd not personally consider an electric at this point.
It is clunky and heavy, likely clunkier and heavier than an electric/cable winch, but versatility is off the charts - I've got a 550' length of rope, the winch can be ~500 feet away, in theory. Or, I can use several snatchblocks and slow things down, or pull it around corners, or hoist snatch blocks up into trees so the rope is pulling up and forward or or or you name it.
I also have a massdam rope puller, which is awesome. A massdam + long snobunjie will do a LOT, if you're pulling forward and can use the motor to assist - dig, make a ramp, whatever - attach snobunjie to anchor, massdam to sled, rope to bunjie, tension the hell out of bunjie, use throttle and push, that'll often pop it out. Or, just use the massdam and drag it out - if you're pulling up a steep hill, using the motor is a gamble - if the track spins, it'll dig a wall in front of itself and make it REALLY hard to pull up and over.
Anyway - imho, consider a capstan. If you're going to drag an anchor around, capstans are, imho, way, way more versatile than electric/cables. I initially wanted a two stroke, figuring I'd be doing funky things at funky angles, but the one I got is a 4t Honda motor with some goofy oiling system that lets it run at weird angles. It is easy to start when "cold" - cold for me is -15F, so not COLD, but it is small enough you could easily bring it inside overnight then put it in a bag wrapped in a blanket & keep it warm for a few hours at least, it is efficient on fuel, plenty strong, eh? I love it. It took some learning, and I've found that I like to use at least one snatch block no matter what, often two - not because it needs it, but to slow it down. I like two better - I'll anchor the the rope to the bumper of the sled, go up to the tree/anchor, rig two snatch blocks, then grab the rope between the two, pull that chunk back down, put it into another block on the sled - the rope has to be flaked well to get that to work. Then, take the remaining leg, run that into the winch, and there's three blocks - winch to block 1 on tree, back down to block on bumper, back up to block on tree, back down to anchor on bumper. Hop on sled, typically start sled and let it idle to make it roll that much easier, put tension on rope, it starts pulling, keep tension on rope, try to feed rope onto rack behind me/not into track, keep sled level, etc etc etc until at the top.
It is not moving very fast, but it turns into a bit of a circus. That said, it is effective, if you need to make roads up steep stuff you can't get up on your own and don't want to stomp out with snowshoes and wait and hope you make it after it sets up.
.02c!
Iain