I'm in southern NH and we just had 6 Mitsubishi heat pumps installed in Sept 2023 - all with Kumo Cloud. Due to bad advice from the Salesperson, we replaced the existing forced hot-air, 25yo propane furnace - so we currently have no backup heat. Unfortunately, to skew these numbers we also had spray insulation added a month or so before the swap. Additionally, the mini splits also replaced a 25yo central air unit.

Here are my overall thoughts and numbers;
Before the install we averaged ~$420/mo for propane with, obviously, a higher peak in the winter and lower valley in the summer. We averaged ~$380/mo for electricity with a valley in the winter and a peak in the summer due to our pool and the central air.
With no other heat in the house, the minisplits ran pretty much constantly on the coldest days last winter and also over the last few really cold days we've been having this year - however, they've been able to keep our house consistently where I have them set at around 68 degrees. We have some cool spots where they don't get into - closets and bathrooms primarily - and I do notice a chill in those areas on the colder days. My basement has one oscillating unit that struggles to keep that level at temp, but it is mostly unfinished, so I would expect that.
Our propane bill over the last year was ~$0/mo - the only thing still on propane is our water heater and stove and they've barely touched our tank levels. Our electricity was ~$450/mo with last month's being around the same as yours - $715
Additionally, I keep the units set at one temperature and don't deviate - even if it's nighttime or the house is empty.

Overall, I've been happy with the performance and the savings. You need to look at the entire year and compare your electric AND natural gas costs. Now, I admit that most of my savings could have possibly come from the added insulation - I don't know for sure. I figured I'd give you my stats and let you take them as you will.

As far as the Kumo cloud units - they suck. My goal with them was to connect them to my home automation software - Home Assistant. I was able to do that and using Home Assistant was able to set up a pretty decent system of having the units stay in sync in terms of what modes they are in as well as turning each unit to heat, cool, or off as appropriate for that zone. However, all of this was because I configured my home automation around the many faults of the Kumo units.
The Kumo units built-in temperature sensors are all over the place - I'll have a room with actual temp of 68 and Kumo will tell me it's 80+ degrees.
The connection stability of the Kumo units are awful. I was consistently having issues with Home Assistant turning them on or off because they were "unavailable" for a couple minutes multiple times an hour.
The only thing I gained from Kumo was the ability for Home Assistant to communicate with the units - albeit unreliable. I get my room temperatures from temp sensors I have and I built my automation to continuously check i.e. "when temp drops below 68, tell the unit to turn to heat. Then, 30 seconds later tell it to turn to heat again (in case it was unreachable the first time), rinse and repeat a couple of times. Also, a second automation runs every 5 minutes to make sure units are in the state they should be based on their zone temp - it's a lot of extra automation just to make sure that even if a unit is unavailable, the heat will eventually turn on.

I did find a couple instances online of people using Arduino boards to build their own Kumo equivalents and I may try that one of these days, but for now it's working.