I played a lot with the Graphene Speed Pro, then started using the Graphene XT when it was released. The Main Difference is that I find the Graphene XT a bit stiffer, so ended up changing my string set up. I liked Alupower or Solinco Tour Bite 16L in the Graphene at 50lbs. I ended up using Solinco Tour Bite Soft in the Graphene XT, and at a slightly lower tension of 48lbs. For Interest Solinco TB at 46 lbs in the XT was about the closest to 50lbs in the Graphene (But i just don't like the overall feel of the 46lbs). Somehow I just served really well with the Graphene XT (better then with the Graphene) and that was the main reason I 'upgraded' to the XT. The XT swing weight feels heavier, where a lot of comment is that the XT has a lighter swingweight, I just don't feel this. I also like the XT Plow Thru..feels a slight bit sturdier. In summary, I could describe the XT the bigger stronger brother of the Graphene, the XT just feels more assured in the hand.