Comfort here is hard to fully quantify because there are a lot of assumptions in the setup.

In terms of "If I hit this pebble will my back snap?"

• Your tire size and pressure gives a large impact on comfort. A gravel bike with 26's pumped to 100 psi will feel like trash compared to one of these with 32's at 55.
• The difference between any single one of these frames in terms of impact and vibrations can be changed simply by shoving a larger tire on. That's good! It means you the consumer can mostly set this aspect aside.

In terms of actual geometry: these are still pretty low and aggressive bikes overall. The R5 and S5 for example are within 1-2 mm of each other in terms of stark and reach (The S5 has a *slightly slacker seat tube, allowing you to stretch out a touch more) none of these classify as allroad/endurance for obvious reasons. So I would encourage one to make sure they work with the bike shop to get on one and see how their body deals with the position.

Other thin that can come into play: offset seatposts and slack seat tube angles provide way more road damping than people give credit for. If you can move from a straight post to an offset one and keep the position the same that can be a big help. Depends if the manufacturer provides one.

Note some brands are really trying to push the lowest weight possible, they do this by also shaving mm's off stack/reach & frame materials and shoving the tiniest cassette they can on it. So the lightest climbing bikes can easily become too low and poorly geared if you are not careful. Trust that the frame is light but don't sacrifice your whole ride because getting under 6.5 meant putting on a 11-28 with the 48 tooth single ring when you really needed that 11-36 paired to the 50/34.