Got lvl 6 half way on csb ken and usually first blue(lvl 2 i think) on others I am using regulary like kisuke, shini yoruichi or hollow ichigo and few others. Curently stopped spending vit on it so I am on a safe side for possible ubp and just getting items from guild instances we clear. It saves me quite a bit of vit and I am not in a hurry anyway. But I think they went a bit overboard with it.. There is 11 levels and you need several items to synthetise into one right from the lvl 2...quite ridiculous if you ask me.. not to mention the cost of vit for personal instances....12 for lvl 90 instance. Havent gone farther then that..dont wanna see how much they want for lvl 120...