Both of these are copies of what has been the best pipe for years. Performace wise, the Dynamite pipe should have a little more grunt. This is mainly due to the header being longer and smoother. If both pipes are the same (and I bet they are) you will be happier with the dynamite purchase.
The first time the guy next to you hits your side and bends your stinger in you will wish you had bought the more modern pipe. If you need to tone down the low end a little just get one of those short headers to put in your box. They will just about make any pipe smoother and easier to deal with.
I have a lot of pipes and I would go with the Dynamite here.
They are very cost effective and quite a good bargain.