I am 3a with fine hair (I just have a ton of it lol), and it works well for me!
-3a/3b, fine, very thick, normal por., normal elast., long, dye- free (CG since Nov. '11)
-CO (As needed): Suave Nat. (usually strawberry) and air dry
-Low poo (As needed): Giovanni 50/50
-RO: GVP CB (experimenting with GVP The Detangler)
-LI: Giovanni DLI or a tiny bit of my co-wash or RO (sometimes none)
-Styling: BYZ Noodle Head Tame your Curls Mousse
-PT: ION Effective Care