I have plants & Loaches. I've had zero issues & the bottle clearly says not to use it on inverts. I've heard all the mixed reviews, as well. Thats why I posted this question. I originally used it to treat a Velvet infection in my Loach tank & it worked very well for that, so I kept using it as directed for prevention of future infections.
As far as Ick is concerned, it also seems to be pretty effective. Last week I picked up 2 oddball clown Loaches & drove them from Dallas to Houston (4 hrs), and dumped them in my tank. Those 2 developed Ick from the ride, but not a single other Loach or Gourami has any Ick & after a week and a half in an untreated tank they would normally all be covered in it. Even the 2 that have it only have a few spots & aren't even acting sick. Carbon is still in the filter & I have added no salt or heat.