First off it is nice to see that they re-speced the aerobar clip-ons. Previous models had the PD T2 plus. I like Profile Design and have no problems with the extensions… but I did have issues with the J2 bracket. This is fixed with the J3 bracket but when buying something new one doesn’t really want to be messing around changing things right away… down the road is a different matter.
Anyways, back to the original question: Slice 105 or Slice force.
First off I don’t have much experience with the Sram line-up… however, as I have discussed with individuals in the past, I would lean towards the 52/38 12-25 cassette set-up. I’ve found that (for me anyways) this is the do-all set-up (if there is such a thing). Added you can still obtain 50/34 chainrings for the gossamer. (but then again you are back to messing with things right away). On the other hand Sram may have chainrings for a 52/38 set-up… don’t know for sure (and again you are back to messing with things from the start).
Second, everything else being equal, the other difference is in wheels… the Maddux are a deeper rim (v-shape rather than toroidal) with round spokes (use to be anyways). I believe they are much lighter as well. The R501A are heavy pigs as compared to most everything else… however they have bladed spokes… if that makes a difference.
All in all which one feels/rides better according to your friend (does one have better mojo)? Is color an issue? Is there a price difference?