I'm very new to the S4, but I've noticed most people have GIAC or APR chips. Does anyone have experience with Nuespeeds version?

Neuspeed is a reputable company. They just don't have the huge market base that GIAC and APR have collected over the years.

It's a chip that will increase the bar to 1.2 and remove the speed governor.

Check the archives on this issue... there's a lot of valuable info for the past two years on the subject.

Edit: I should also say that the Neuspeed chip gives a smooth (albeit not so strong as GIAC or APR) progressive power band.