It's been just over a month with the G80 M3 Comp, and I'll eventually post a video review on my fledgling YT channel (I'll edit this post later) but for now I just wanted to hit some highlights...
Previous Sports/Enthusiast Car Ownership/Experience:
-I've owned a couple of different E46 M3's, the E36 M3, and an F80 Comp, and have driven the other generations quite a bit. Several of the later generation TC 3 series, a 5.0 Mustang, etc. Most recently, a 991.2 911 GTS.
G80 M3 Comp PROS(IMHO):
-Immensely comfortable car to get in and out of, drive, live with day to day, etc.
-Beautiful car aesthetically. I love the profile, and I "got over" the front end years ago and now actually think it compliments the car well. Aggressive looking stance, sexy, stylish while also looking luxurious.
-Technology is excellent and a huge step up from the 991.2 Porsche. I love the larger iDrive screen, the lighting options, the layout, etc. I still have occasional weirdness with the radio switching to other options, and/or the screen being a little "possessed" but that could be from my own idiocy
-The power is unreal, truly. When I
think it's ready to drop off it just screams for more. An absolute beast in the straights/highway.
-I'm very impressed with the steering, both generally and with corner entry/exit. Now, it's definitely NOT the 911 GTS in terms of precision sharpness, and feel, but for the size of this car and class that it's in, I find it excellent, truly. I've heard some mention they felt steering to be too "numb" or there was too much understeer but for the most part I'm not experiencing it with my car (wearing Pilot 4S). It handles wonderfully for a heavy, large saloon with a whopper engine.
-Brakes (we'll get to the sounds later lol) are incredibly grippy, nearly terrifyingly so
M Brakes have always been killer but these seem a bit extra.
-Overall there are a lot of good things to say about this car. Awesome daily driver providing a lot of joy, unquestionably.
G80 M3 Comp CONS:
-The brake squeak
I mean, I've seen all the videos, owned a bunch of other M cars, etc., so I'm well-versed in the bedding in process, the excessive brake dust, and the "drive it fast a few times and nearly lock it up," yadda yadda yadda. I thought, after trying the last method, I had "solved" it shortly after buying the car but...nope. As others have posted, it comes right back
For a 90k+ car, it just seems absurd that they can't source materials (that other vendors apparently have) and put on a setup that doesn't sound like a school bus coming to a screeching halt at stoplights lol. I will be switching to the iSweeps ASAP.
-Gas mileage is not as bad as I recall the V8 M3 being back when I drove it rather extensively,
but it ain't great 
Having said that (in best Larry David voice), I knew what I was signing up for, however, didn't expect it to be quite this thirsty (I'd say guesstimation is 20% thirstier than the GTS...but that's far from scientific lol)
-The transmission is certainly not PDK precise, but overall it's fine, although I do get a lot of "clunky jerkiness" when exiting parking lots over uneven surfaces or sometimes when I'm in traffic and just tapping the throttle to move forward. Far from butter smooth, but the shifts are precise and quick when getting on it so not a trainwreck
Overall Rating (so far after 1 month of ownership), 1-10 scale for each:
1. Power/Performance = 9
2. Styling = 8
3. Handling = 8
4. Brakes = 7.5 (maybe a 9 if not for the insane squeaks lol)
5. Comfort = 8.5
6. Technology = 8
7. Efficiency = 6.5
8. Daily Driver-ability (storage size, ease of access, etc) = 9
9. Passenger Comfort = 9 (wife loves it overall)
10. Smile Factor (how much do I smile and get excited when about to drive it...a number that will certainly increase when I get the brake pads swapped
) = 8.5
Overall 1 Month Score = 8.2 
Absolutely enjoying the car, and although it's not quite the machine that the 911 was, for what I'll be using it for, and just overall day-to-day drivability, it's a wonderful car
