First let me say I have been lurking here for a weeks and have learned a great deal.

We are finalizing the details on a pool to be built and the builder has spec'd a Nature 2 Fusion Soft SWG. Link: http://www.nature2.com/poolproducts/inground/nature2_fusionsoft.asp I know the consensus is that the general Nature 2 mineral additives are not worth the expense, but I was wondering if this is a good SWG and if I decided to not use the mineral cartridge if it would impact performance.

Or should I just spec a different SWG such as the Jandy AquaPure

Welcome to the forum
That is exactly what I would do. Why bother with something that is/can be detrimental to your pool?