Anybody buy one? Are they easy to install? Do they need to be charged with coolant?

Watching this with intrest. I also have been wondering about them. Ones at work worked. But I dont know details your asking.

Some come pre-charged, others don't, If your comfortable running electric than it's not a hard install...

I went with a HVAC install of a Mitsubishi in my new shop. It did not come pre charged. Took two guys about 5 hours to set everything and run all the lines. The electric had already been run so they just had to hook it up.

Not mr cool but I have installed 4 Garvee units in my house by myself and I'm not an hvac guy. Well worth it.

I've installed a couple Pioneer units in my house and a couple for others.
Happy with them

I have a MR. Cool 24,000 BTU DIY mini-split in my Michigan cabin. My son and I installed it in about 4 hours, granted I had previously installed the electric service. It came with recharged lines very easy to install.
I use it to cool and heat a 750 sq ft cabin. Cooling is great, can easily make it to cold. Heating works good to about 20 degrees outdoor temperature then it still works well maintaining indoor temperature but it has to go through defrost cycles two or three times per hour. I have used it in subzero temps and it still works fine except for the defrost cycles. In the really cold temps ,teens and below, I have started using an electric portable heater instead. I have 4 years on the system.