It is actually quite useless to order "THE kithai epic gear" in tiers. As mentioned the sets from the different factions offer different main stats, so you can prepare your toon for a lot of different situations and tasks. Of course there is the obvious dps-road, but even that is not a safe bet in all cases. The second reason is that not all pieces are by all means superior to T3, as not all T4 pieces are superiour to T3,5. You always have to think about what you want to do with that toon, and what gear you already own, and what gear you can get, and which content you want to play to get it, or which content you plan to enter with the toon.
So my advice would be to look at each piece and compare.