Just from what I've seen the 2.0 cams would give slightly better performance and slightly smoother draw. I had one earlier this year with 1.5 cams and could not get the draw length short enough for me. I shoot 26 3/4" and although the S-5 was listed at 26.5" to 30+ the shortest I could get it was 27 1/4", that after adding 15 twists to the string and 5 less twists out of each cable. This years model is listed at 27" on the short cams. Go figure.
If You're Not Living on the Edge You're Taking Up Too Much Space
Martin/Rytera Staff Shooter
PSAA Life member, UBP Life member
PADI AOW Diver