I'd gotten some bunashimeji (brown beech) mushrooms among others at H-Mart about a week or so ago. I tried cooking up the cute little bunashimeji in some sesame oil and scallions, and it initially smelled good. Then an odd smell started coming up as the mushrooms cooked - I tasted one and there was an off flavor to it too. Even the addition of some soy sauce did not improve the flavor. Into the trash it went, which annoys me - anyone who knows me knows I do not throw food away unless it's utterly inedible.
They didn't seem to be rotten in any way, no sliminess or bad smell in raw state. The information I found says that they should last up to 10 days in the fridge, and I prepared them within that time. I guess I just found a mushroom I don't like. I did like the maitake ("dancing mushroom", hen of the woods) mushrooms I made the other day with steak even if I oversalted them. Maitake are supposed to be quite good for the immune system.
Bunapi shimeji (white beech) was good in soup - which is odd because it's pretty much the same mushroom as bunashimeji, just as white button mushrooms, baby bella/crimini, and portobello mushrooms are the same species
Also yummy: Enoki; Eryngii (King Trumpet, King Oyster) though Broccoli Boy was less than thrilled; and my much beloved Shitake.