Everybody has their own ideas about what a "good" or "bad" sound is. Fortunately, there are a lot of guitars, amps, pedals, ect to choose from to suit YOUR needs/desires.
My experiences with Gibson quality after owning many SG's, Les Pauls, ES-335s, ES-135s, ES-137s, and Firebirds :
1. I came across an
SG Supreme with a 24th fret that was coming very slightly out of the fretboard on the high e-string side. Aside from that 1 fret that needed to be re-seated, I was able to set the action very low with minimal buzzing (I play with a very light touch, so YMMV). The fret-finish on Gibsons doesn't seem to be as polished/smooth as some other guitars I've owned. It's certainly not bad. But the frets don't "glitter" as much as frets on a couple $ ESPs and $$ Jacksons I've had.
2. Some Gibson necks are very thin and are sometimes more susceptible to up or down bowing. It's really thin. If you want thin, then you deal with it being slightly more flexible. Of course, the thicker Gibson necks don't flex much. All guitars do to some degree.
3. Gibson's binding starts life as tall as the frets. It is then ground down between the frets to match the height of the fretboard. This leaves some binding that extends up to the height of the fret, right next to the fret. Sometimes the grinding is done sloppily and you will notice grinding marks on the top of the binding. Or worse, you'll see where the "luthier" hit the front of the nut with the grinder. I have guitars with the binding up to the top of the fret and have had no problems with it. Of course, if the binding next to the fret starts to chip, you will have a sharp, irritating, exposed fret end (the "fret bevel" is on the binding, not the fret...you lose your bevel if the binding comes off). I also have Gibsons that I pulled the frets out of and replaced them with notched tangs so that the fret itself extends the full length of the fretboard without going through the binding. I prefer a full length fret, but have had no problems either way.
4. I have never encountered an electronics problem with any Gibsons I've had, new or old. The pots and switches always feel firm and of good quality. I prefer Dimarzio pick-ups with an extra switch or two. But I know many people who love the stock Gibson 490s and 500s. I've never had any hum/noise except on P90 equipped SGs and ES-135s....which is to be expected from single coils.
5. The Gibson nut is ok. I don't know what it's made out of, but it is somewhat soft and I have seen 1 or 2 that have started to crack on the low e-string side. Although I've never had a problem with the stock nut on any of my Gibsons, I do prefer a bone nut and have installed them on a couple guitars.
6. I've never encountered a Gibson with wood that didn't seem of good or better quality. The finish on the body/neck has always been pretty impressive to me. Some of the finishes are just absolutely stunning. I don't recall any overspray, runs, ect except like what is found in most guitars...a little going into a pick-up or control panel cavity.
7. Gibson head-stock angles are steeper than Fenders, Ibanez, ect. If the guitars falls back wards, the tip of the headstock will hit the floor first. And there is a good chance it will break. It's never happened to me. But it has happened to a lot of people.
8. Gibson tuners have been fine for me. I've never wanted or needed to change them. They have never been an issue when it comes to keeping my guitars in tune.
9. Gibson bridges : I have never had an issue with any of the bridges on my Gibsons. I've never had a Gibson that had a problem staying in tune. And I like that you can usually tweak the bridge up or down without tools. Adjusting intonation on the Gibson bridges has always been really easy. Personally, if a guitar doesn't have a tune-o-matic or an Edge Pro, I probably won't even consider buying it....that's my preference.
These are some observations of Gibsons I've owned. I've also owned many other other guitars by Jackson, ESP, Gretsch, Ibanez, Taylor, Ramirez, Fender, ect. And there's not 1 of them that I couldn't "complain" about to some degree. If I get a call to go out and jam tonight, there's no question in my mind....I'll be reaching for my '61 reissue SG. Why? because it is THE BEST GUITAR...for me.