5.2
I have about 650 miles on a 2014 Domane 5.2. I came from a 2004 Trek 5000. The 5.2 is better in every way, the 11 speed Ultegra is smooth, I don't take the beating that I used to on crappy SE Wisco roads, it spins up quickly, my neck and back feel better after a ride. My LBS took almost $500 off of MSRP, and sold it to me for $3,200. All I can say is that I have 0 regrets although I was hesitant to spend that kind of money, I'm very glad that I did.