I love mine...I've had it since September but only rode it through early November until the snow pushed me back into the basement.
I was coming from a Domane 4.5 (Caliper). My opinion is as follows:
The front Isospeed on its own provides a modest (possibly underwhelming) improvement in vibration attenuation. Likewise, the effect of the Isocore bar is again, subtle. This is relative to the existing isolation provided by the seat-tube Isospeed which anyone whose ridden any Domane has experienced.
The most dominant improvement I enjoyed in moving to the SLR was as a result of choosing the disc version - I am able to run very wide tires (32C) at lower pressures - by far the most dramatic improvement front and rear.
The cumulative effect of all of those technologies come together to create an extremely comfortable and stable road bike for long hauls. I look forward to riding it on the GFNY in a few months with my new Enve 4.5 AR Discs.
