I have a 2016 Domane 4.0 Disc with 9 speed Sora and a 2014 Trek Madone 3.1 with Tiagra FD and 105 RD stock from factory; it is 10 speed with rim brakes.
I like the Domane better and have no problem with the Sora. However, I am 70 years old any run out of gears on hills; I don't stand and pedal. I likely will upgrade the Sora groupset to 105 on the Domane not because I am not satisfied with its operation, but rather because I would like a few more gears to keep everything trimmed and burning.
Mike