They are both good sticks, so you probably aren't going to get someone here to bash one and tell you to get the other (not that you were looking for that). It really depends on what you are looking for in a joystick. They both have different feels. The switchable 4/8 ways aspect of the Tstick is a dealmaker for a lot of people, and you don't have that with the Comp. Some prefer the Comp for fighters, some even the Super for fighters. It also depends on what games you play most to an extent.
They will both work, and both will have fans here on the board. I'd say you should consider getting one of each if you're ordering from Happ and Ultimarc anyway, but I don't know if that is the case. That way you can try both, still have a 4way to use, and make your own decision. Worst case scenario: you decided to get 2 of the same stick, so you have to sell one here. It won't be too hard for you to sell either of those joys in the FS board.
Just my .02 Someone here will probably be able to give you a much more technical breakdown of the differneces, I just prefer to play with them and see what I like more.