At 5'9 - 5'10, I'm always between most manufacturers' 54 and 56 (ETT) frames. I know the advice is to size down because you can always make a smaller bike bigger, but that didn't work for me. My last bike I sized down to a 54, and after purchasing several stems, multiple adjustments and a year and half of riding, I never was comfortable. I just finished a build on a similar frame, but with a 56 ETT, and everything feels "right" again. For me and this frame, sizing up was the right choice.

I think you look fine on that bike, and obviously it's going to come down to how you feel on the bike and your comfort level. I think once you are able to get in a few longer rides, you'll know for sure if it is right for you.