I upgraded from a 2013 Domane 4.3 which ran the Shimano 105 group set. The first thing I noticed was how much lighter the 5.9 Domane was. The next enhancement was the incredibly smooth and reliable gear shifting with the Dura Ace group set. Just fantastic! The integrated seat post added an enhanced level of compliance and comfort over and above the incredible effect of the unique Trek Isospeed De-coupler system. This is one comfortable bike! The Bontrager Infinity saddle is very comfortable too! The Titanium seat rails are just there to boast about because it is just cool to say "I have titanium seat rails!" They make no difference to my ride except in the contribution to lowering the weight of the bike. It is significantly lighter than my 4.3 Domane! My first day of riding extended over 9 hours and 200 kilometres and I didn't feel saddle-sore in the slightest! Even better, and perhaps more noticeable was that I had no aches in my neck and wrists through road noise. Even though the 4.3 has the Isospeed forks, just like the 5.9 version, it was the Isospeed handle bars on the 5.9 that made the difference with gel inserts that absorb volumes of vibration. Again, perfect for an endurance bike. The standard wheels are the Bontrager Race Lites with R3 rubber to the road. This combination is tubeless ready, however, I use tubes still. They weigh in at just 1600 grams or thereabouts. They are fantastic! I have included some photos of the bike in delivered spec, however, I have since upgraded my wheels to the Bontrager Aura 5 set and have included new photos of the bike in the new set up. It looks amazing and I have added about 2.5 Km/hr average to my speed without extra effort. If there was one thing that has taken me time to get used to it is that the reduction in overall weight has made the bike less able to hold a straight line if I take my hands off the bars, to adjust my helmet for instance. I just have to work a little harder to stay straight and upright and to be fair, after just a little while, I got used to it. I love this bike and thoroughly recommend it. I am also a fan of the "Stealth" appearance of the matt gun-metal grey frame. Go Trek! Go Domane 5.9!