Choosing between the Canyon Aeroad and the Canyon Ultimate comes down to particular requirements and specifications. The Aeroad is said to be a little slower than the Ultimate on vicious climbs and flat sections, but a there’s still a fair tradeoff as it’s more aerodynamic in the first place. The Ultimate is lighter and arguably more pleasant, hence possibly better in the descents. Both bikes have very similar geometry so the fit is expected to be more or less the same. In the end, there aren’t strong distinctions between them, and both are great bikes. In this context, fit and comfort level should be regarded as more important considerations than difference in weight of a few hundred grams.