I am doing my very first hydro grow right now and using Supernatural GroAqua. It's working beautifully and it's very easy to use. I'm using it 1/8 strength right now (my plants are seedlings) and they're plugging right along and growing rapidly.
For flowering I'm using FloraNova one-part bloom. Of course I don't know how it works yet but I bought it because the hydro store near me didn't have the Supernatural BloomAqua, and having seen the good reviews of FloraNova on here, I felt confident buying it. The guy at the hydro store said FloraNova nutes were his favorite.
For a total hydro noob, however, I feel totally confident recommending Supernatural. I'm not having any of the problems I read about others having with nute burn. Of course, I'm also using way less than the recommended amount. Thanks to all on this site who taught me that!
Re: Superthrive -- I'm using it in my reservoir, one drop per gallon. So far so good. I'm also using it on my outdoor soil plants with good results.