I use it quite a lot. It might be somewhat cheesy tasting, in a sense, but as far as I'm concerned if you can taste it, than you used too much.
I use it simplify to add umami to vegetarian food where I don't want to add other ingredients that affect the taste. It's a bit like MSG in that sense. I also use MSG, but I find its flavor notable as well, sometimes more than the yeast. I'll often add a touch of both if I want a lot of natural umami.
Note that it should be cooked to get rid of volatile yeasty aromas.
