I've used it a couple of times in my beer and never noticed any off-flavors and it really does the trick in a turkey fryer when you only have maybe 1 inch of pot above the wort.
I've also had some brewing sessions where the boil just seems to behave itself and the drops were not necessary. Haven't figured out why exactly yet.
I did a stout a couple of weeks ago with McStout and we used gas drops from the store. Tamed the wild foam. We'll see soon how the flavor turned out.
And as an FYI, I boiled a small amount of wort separately on the stove, and that did not get the drops. The 2 quarts of beer that did not get the drops developed a LOT of krausen. My very quick peek into the bucket of the stuff I used drops in seems to have little to no krausen marks. I am thinking that the stuff managed to get transferred into the fermenter from the kettle, as I no-chilled the kettle outside in the snow and poured it through a strainer going into the fermenter.