This topic is dangerous to discuss for me, mainly because I oppose replicas / counterfeit bikes. I have seen more than a few of them attempt to be passed off as the real thing, including in secondhand sales. Creators shouldn't have their IP ripped off--and that includes brands. Counterfeiting is not a legitimate form of protest or artistic impression. I also question where the money goes and what level of engineering goes into these frames when the objective is to make a looks-like copy rather than a product that stands up to use. Further, a lot of these sellers tend to come and go. All in all, it's a risk I wouldn't take on a frame.

With that out of the way. Here is the second disclaimer: I am about to engage in some armchair / principles-based engineering, which is never high-quality commentary. Generally speaking, the external shape of the structure will have more influence than the wall thickness and layup used on stiffness and strength. Square-like tubes are also easier to make stiff in a specific direction than round ones. Complex aero shapes present a problem to model, and companies will try to do a lot with the layup, but it's very much trying to optimize a tube shape that, from the outset, doesn't make for a good double triangle-based bike. Round tubes are light for their stiffness, are easy to make predictably because of the lack of corners in the mold, and are a relatively simple / known problem to work with. The SL8 has an aero-ish front triangle and a round tube-based rear triangle. The Aethos is a round tube bike. If you want a bike that is more likely to have a great ride feel, the answer is to go with a bike that uses mostly round tubes or a mix of round tubes in the rear triangle and square ones in the front triangle. The engineers are more likely to get that right than a design like the Canyon Aeroad.

My $0.02 is that if you like the Aethos look for another round tube bike. There are plenty of open molds (there is an ICAN) and Chinese branded frames (like the Bigrock climbing frame) that use primarily round tubes.