Not in terms of vertical compliancy. The Roubaix SL3 rides like a cloud but is torsionally very stiff. Why the Roubaix SL3 is universally loved is...it has the power transfer of a R3 and a ride perhaps even better over rough surfaces compared to the RS. Credit Specialized for this elusive balance. I have stated before that Specialized R&D runs very deep. Look at all the great products they make...in particular their saddle technology is second to none...make great shoes etc. This is no slight on Cervelo, but in my opinion, Specialized makes the best production bikes.
It was Specialized vision that created the comfort road bike genre really with the Roubaix. Also...for larger frame sizes...for example the 58 Roubaix has a head tube length of 225mm versus 200mm for the RS...and 199 for R3.
The RS is a great bike but as I mentioned, I believe the Roubaix is the king of the comfort bikes. I have a CAT2 buddy who races a Roubaix because he likes to ride a bit more upright and it doesn't hold him back.