I remember looking at some point, and Gnome had roughly 4x the number of developers that KDE had. If you want the best (most stable, most well tested, most feature full, etc.) programs, you basically have to use some Gnome programs. That was one of the deciding factors that pushed me to go with Gnome. If I was going to have to use Gnome programs anyhow, and they worked best with Gnome, then I thought I should use Gnome. My experience was that Gnome programs don't really play well with KDE, but that KDE programs generally work OK on Gnome.

I really like the customizability of KDE, but I like many of the defaults of Gnome. Unfortunately, if you don't like some of Gnome's defaults, it's real pain in the ass to change them. Personally, even though I liked a lot of Gnome's defaults, I absolutely hated some other ones. If it weren't for extensions there's no way at all I could use it. Luckily, some of the biggest misfeatures are so widely recognized that there are dozens of extensions to choose from to fix them. OTOH KDE's customizability led to some issues too. I remember having some weird interactions between things because settings A, B and C don't necessarily work well together. But, at least those settings are built into the desktop environment, and you're not relying on some random dude's hobby project for a critical system setting.

At the moment, I'm pretty happy with Gnome, and most days it just gets out of my way and lets me do what I want to do. That's something I never ever got with Windows. It was always a pain in my ass. And, it's something that was only ever 90% true with OSX. Great defaults, but that last 10% is a real pain in the ass. Gnome's extensions let me get much closer to 100%. I have to admit though, that I do dread the day that I have to upgrade it and all the extensions break.