Warning. I'm very opinionated on this sort of thing
I didn't look at Mitsubishi. I know they would be thousand's and must be installed by a dealer. Efficiency wise I suspect they are close. Long term reliability my guess is Mitsubishi would probably way out last these units, more serviceable, easy to get parts etc. But you never know. If I were building a new house and wanted mini splits, that's probably what I'd do. You'd still of course qualify for all the rebates. But it's not gonna cover 100%
Only difference with MRCool is they sell pre-evacuated lines for $300.00 extra so you don't need a pump, vacuum gauge, and valve and learn how to use them. You plug them in like you do your propane tank on your grill.
I just took a peek. A comparable single zone 24K BTU 21 SEER Heat/Cool Mitsubishi is $2600.00. Plus installation. My guess is they would charge min $1000 to install (wild guess). Technically you'd need an Electrician and an HVAC dealer. Not sure if many HVAC installers are qualified to install the circuit, they might be.
I'm sure the Mitsubishi would be higher quality. But keep in mind. What lot of reputable companies do, to compete, is the buy the same low end non branded stuff from China and slap their label on it. Like if you buy a John Deer riding lawn mower at Home Depot. That's not a "Deere". It's the exact same unit as the MTD, Crasftman, Yardman painted different colors. But they will get the job done. Mitsubishi might be doing that on their "low end" models. Not sure. Just be aware of that, often you'll see different warranties on the low end vs high end.
One way to tell is, Mitsubishi can now handle really extreme low temps, like -20F. The unit I got can go down to 5F. If it's rated to -20F or similar, it's probably the real deal and worth the extra cost in the long run. I'm out of here when it drops into the low 20's.
Also keep in mind that Home Depot just finds local guys to install stuff. It's not like they have a certified team. Didn't see mention of installs. But it's a bit of crap shoot of Big Box store installers. But I'm sure they would back it if you go that route (get the extended warranty
) You probably won't over pay though if you went through Home Depot vs if you go to someone directly they might rob you blind.
For example, I just had a well installed. It was quoted $8-$12k. It ended up costing me more like $20k+ (with some MINOR upgrades). A neighbor (next lot over) saw them and asked for a quote. $30k !!! And $15K for water filtration system. That is robbery. They are one of the most popular well drillers in the area. Oh and they also didn't know what they were doing and I had to reconfigure the controller to match what they actually installed.