I'm unrelaxed...but when I did relax, my stylist applied an Affirm Fiberguard and I ended using Mizani.
They are both very good relaxers. My hair is very "thick"..i.e. coarse. I'm a 4A 4B mix. My stylist chose a LYE relaxer because of this.
If you self-relaxing, there are great reviews on the Olive Oil Relaxer. No-Lye (in the box), and LYE (in the green container). But, if you're not a GREAT self-relaxer, I would say the box Olive Oil relaxer (NO LYE). It comes with everything you need and works wonderfully for setting.
Try the search button...
You'll hear raves about the No-Lye Olive Oil Relaxer and Mizani Butter Blends. Both are available in your local BSS.