I have a 12K EG4 mini-split, installed a couple of months ago in my 16x22 off grid office. Works very well but I have used it only for cooling thus far. I had a 9K at a previous property and it worked fine, but I used it primarily for cooling as well. Extremely quiet, and most of the time uses only about 200-300w. I think the most I've ever seen it draw is 650W, for maybe 5-10 min. Installation is easy if you are handy and directions, indoor template, etc., are much improved over the original 9K I installed. I did it all myself but a second person to help lift the indoor unit would have been better (my upper body strength at 60-plus isn't what it ws even 5 years ago, but I got it).
All mini-splits use more power for most heating, in part because the delta temp you're trying to overcome is usually greater. If it's 90 outside and you want a 70 degree room. that's just a 20 degree difference. If it's 30 outside and you want the same indoor temperature, that's a 40 degree difference. And given that they just concentrate and move heat, there's less "raw material" in cold air, so they must work harder to capture it. I expect my unit to need 600-1000 watts for most heating requirements, and I doubt I'll use it at all below about 20, but we'll see. In vey cold climates like ours (Maine) I'd have a backup for these units. My Mitsubishis in other buildings don't require that, but they cost 2-3X more and are designed for -22F. These units just aren't built for that, but they're not at that price point, either.
Would I buy another one? Yes, I would. They're not as good as our Mitsubishis but I like them better than the Daikin mini-splits we had in yet another property. A decent value for a DIY unit if you don't want to deal with pumping out the lines, etc., required of most other mini-split installs.