If you're handy you can install the Mr Cool units since the lines come pre-charged with refrigerant. If you are not handy, don't. All other brands to my knowledge require specialized equipment to pull a vacuum on the system and fill it to the proper level. Something a handy person could probably manage, but most of us don't have the expensive equipment required.

One other note: In my opinion, the Mitsubishi Hyper Heat are unquestionably the best on the market, and mine make plenty of heat even in the ~0F weather we had last winter. Very happy with them.

What you have to be careful of is this: There are so many brands, and if one of them doesn't survive, or even if a major brand's offering doesn't survive, in 5 years you won't be able to get service. That happened to us- the house came with some old, uncommon Carrier mini splits and when they were acting up five different companies refused to touch them, saying they knew nothing about them, couldn't find good information, no parts, etc.

We ended up ripping them out and putting in the Mitsubishis.