How cool, building a bike. The one argument I see for a SRAM groupset is that they have 11-32 cassettes (PG 1050 and PG 1070), compatible with Apex, Rival and Force. Shimano has up to 11-28 only.

When I was shopping for my bike, I tried SRAM and I really liked it. At the end, it would have entailed a higher price for me, so I stuck with Shimano. The SRAM components are also significantly lighter than the Shimano counterparts. My next bike (when I win the lottery) will have SRAM Red!