It depends.
If you want to PvP and never PvE ever then Gladiator Suite is the best. It is optimized and tailored for that specifically.
If you want to do everything then Tuanha is great for PvE such as raiding, questing, grinding, whatever. It is also pretty good for PvP the more you play yourself the better it is. If you use it for rotation and CC yourself and maybe use certain defensives yourself then it can be great. The more automazation you need for your PvP the more Gladiator Suite pulls ahead. Millz is pretty good for Shadow Priest if you only played one spec which most people do not. Richie's routines are also pretty great, I have achieved my highest rating using Richie's Disc routine, but you have to pay for each spec and if you want all 3 specs then it is by far the most expensive option.