"Best" is a relative and subjective assessment when it comes to the pre-order armor sets.
All three increase your sprint ("Storm") speed by 10%.
Terminus armor boosts your shield total by 15% and gives you an extra thermal-dissipation "clip" for your weapons (meaning you can fire your weapons slightly longer before having to "reload" or find new clips).
Inferno armor increases power damage by 10% and your negotiation bonus by 10%. Note that the power damage increase applies to ALL offensive skills, not just biotic powers (since each class' damage-dealing skills are apparently treated as powers). The negotiation bonus applies to your Paragon/Renegade persuasion attempts, meaning NPCs will be slightly easier to convince.
Collector armor raises your health total by 20% and your regeneration rate by 10%.
So each one does different things and which one is "best" will depend on the way you play and/or which one you like the looks of best.