Jack3d or any preworkout isn't going to be the thing giving you the results. The aim of a preworkout is to help you push harder. At the end of the day it means you can push yourself harder for moreworkouts and once your diet is in check with your goals, you'll see results.
If you're not getting results now, a new pre-workout isn't going to help in my opinion, so if you're switching just because your not getting results fast enough, then don't. That said I'm not particularly cool with having DAA and NDMA in a preworkout, more so had bad experiences with NDMA...
I'd vote for getting some good results first if you're happy with the energy you get from jack3d and then experiment with new pre-workouts. If you're not happy with how you feel on jack3d, but all means try something else.
My 2 Cents