In the last few months I have completed my pvp t2 (aka minigame armor) and dinged pvp lvl 10. For the lack of anything better to do I have decided to get my t3 armor. No, honestly I went for that armor because simply I adore it's design. There, I have said it: t3 looks better than t2. I am writing this post to show you that at the end of the day it pretty much boils down to your preferred pvp look rather than stats because difference in those is marginal AT BEST.
Assassin armor is pretty damn unique in post 1.6 reality because those are pretty easy to distinguish. While ranger/barb got their copy/paste job assassin's armor differs in lack of face cover in t2 and overall tone. T2 armor is dyed in stylish black and because of that it can be mixed and matched with other pieces of gear for vanity. However lack of face cover makes the hood pretty weird looking, especially on male character. The T3, because of it's golden-ish color, is very ornate and the mask makes the whole package very menacing. The T3 also is completed with matching cloak that gives it that finishing touch. I like it and I cannot lie!
For the purpose of stats comparison I have striped my character of accessories (cloak, rings etc.) and weapons. What you can see below are "naked" stats given by T2 and T3 respectively.
In "PVE" tab (aka universal stats) the only difference is 0,3% critical chance and 1% critical bonus damage.
In PVV tab there is 0,2% difference in evade chance, 1,4% hit bonus chance (almost meaningless stats) and 0,2% armor. Combat Damage increase is 5 ...out of 130.
Obviously don't get both of them like I did :X I would say go for the one you really like design wise because stats difference is marginal at best. I got my T3 armor via combination of Bori farming (around 3.000 tokens) and drops from kills in minigames. In fact I wouldn't had to do any Bori at all if I hadn't spent my conquest tokens on prowness. Even a laid back approach to minigames can land you around 250 conquest tokens per week and before you will be pvp lvl 10 you will have more than enough to buy full armor.
Last thing that I have to mention is that ever since I got T3 armor I am focused in minigames a lot more. Somehow (and I am guilty of that too) assassin in T3 is perceived as a much larger threat than the one donning the black suit of armor.