I doubt you'll feel a difference with either one. I went through a bunch of stems: Stock System Six, 3T Arx Pro/Team, Deda Zero 100 SC, Zipp Service Course SL, Easton EA 70/90, and now a FSA OS 115. They all pretty much felt the same...with the exception of the System Six one...that felt like a jack hammer.
Get the one that looks best to you.