There is nothing terrible about StressCoat. Like a bunch of other products, it neutralizes chlorine. Unlike Amquel or Prime, it does nothing for ammonia freed when treating water with chloramine, but if you only have chlorine in your water, who cares?
Many of us are highly skeptical whether the aloe in StressCoat is beneficial or not, but at normal doses it doesn't seem to cause any great harm, at least in the short term. (I find it hard to imagine that it helps fish to have gill tissue covered in aloe, but that's not really germane to the present discussion.)
There are lots of dechlorinators that are considerably cheaper than StressCoat, but it's not a horrible product. It just contains stuff than many of us would rather not have in our tanks, and you do pay for that extra (unwanted, in my case) stuff.
If you have chloraminated water, Amquel, Prime or AmmoLock2 are much safer (if you don't age your water). They neutralize the ammonia as well as the chlorine, making life a bit easier on your fish.
HTH,
Jim