yes ~ I have used it (for jboy)
yes ~I would recommend it
yes and no ~ teething gel was INSTANT relief, the brauers takes a bit longer to kick in.
I dont know about Hylands, I never used them.
No side affects I was aware of
Its a homeopathic remedy, I *think* it needs to be dosed a few x a day, starts working withing 6-12 hrs, but it really seemed to work for us.

I used a mix of bonjela/wcH teething gel, and the Brauers, a few times after having the brauers Jboy had teeth come through and we didnt even realise.