In the spirit of parity, I'll reserve my pick (because I don't want to come across as biased), but I do want to say that too much TTA isn't necessarily a good thing either. There is one study to show a minimal difference between 600 and 1000mg.
In the spirit of bias, though (because I can't help sharing), I'll say that I would personally go with Decimate/TTA-500 for budgetary purposes. Sprinkle a little caffeine in there with the Decimate dosings and all's right with the world.