The thing is, that reddit is not a community. It's a place to share images and have discussions, but because it is a lot to do with images, there isn't a great deal of community forming. I've been on /r/mechanicalkeyboards for about 18 months to two years, and I honestly don't know anyone on there other than ripster and few guys from here who post there.
I don't prefer GH to /r/MK, or visa versa, but I think both are good for their own things. GH for community/discussion and a general fountain of knowledge, /r/MK for pictures, announcements and random facts you never knew. IMO, ripster knows his ****, and his imgur albums are actually really interesting.
The reason why every other post is a QFR, is because, like some of you have said, reddit is not a place to find in depth stuff about individual and specialist topics. people go there for a quick blast of information, lots of topics get posted and moderation is not as strict as it is here. This results in people who browse reddit looking at other things, find out about mechs from /r/computers, /r/buildapc etc, get linked to /r/MK and it escalates from there. The karma train then exists because the etiquette is a lot better on /r/MK than some of the other subs. People who post QFRs are seen as newbies, and people just let them show off their new board.
There are of course some interesting picture posts, some custom boards, some nice unique things, along with your usual reddit memes and stuff. But it is just a stop and go.