I read the bicycling sub over on Reddit, and the cycling sub (the only two Reddit subs I ever read) and they are always trashing the Tourney groupset. This makes me angry, because my mountain bike is a 7X3 with Tourney derailleurs, and it's the smoothest shifting bicycle I own.
I ride four bikes, and none of the other three, which have "better" derailleurs on them, shift as quietly, as easily, or as accurately as my Tourney mountain bike. The shifts are so quiet, all I can hear is the "click" of the rapid-fire shifter. They are so smooth, sometimes I shift the other way just to be sure that the derailleur actually shifted. But they never skip gears, never double-shift, never fail to shift. They are just as smooth going up hills as on the flats.
There is no rubbing in any gear combination which means I can (and do) ride in 7th gear in the little ring, and 1st gear in the big ring. These combos are as silent and as smooth as any others. I love the Tourney groupset! I wouldn't mind having it on my hybrid, my flatbar roadbike, and my road bike.
I guess what I'm saying is, if you are thinking about buying a bicycle and the derailleurs are Shimano Tourney, don't let that put you off. I think most of the people who trash Tourney have never actually ridden much with Tourney. Of course they need to be correctly adjusted. It took me a while to get my Tourney derailleurs dialed in the way I have them now. But when they are right, they are sweet!