I have a Ribble Endurance SLR with Ultegra Di2 and the Zipp wheels.
I came from a 2013 Focus Izalco with mechanical Dura Ace and rim brakes.
The Ribble was tempting as cost considerably less than the big brands for the same spec.
There are a few little finish bits where you can see why it’s cheaper. Ports on the frame for cables that aren’t used, a bit of paint around the bolt facing. Nothing show stopping but you can see why it’s not £8k like the SL7 Expert was.
I fitted a 34t cassette (Focus was 36/28 – a bit tall for 20+% gradients where I often ride – Peaks, Dales, Lakes), went from 140 to 160 rotors (I want the best brakes possible) and set it up tubeless.
In terms of speed, it’s no faster, in fact feels a little slower. However I can ride it much further as it’s more comfortable for me. My usual distance is 25-30 but I cracked out a few 45-50 milers straight away, no worries.
The gears are so crisp and the brakes so much better and confidence inspiring.
The name is misleading, it’s called Endurance but geometry very similar to other brands race bikes, so while it’s much comfier it’s still a grand tour capable setup (just what I need for a lunch time ride round the Dales or Peak District!).
I had one issue where the firmware wasn’t updated which the PDI check should have done, but they helped me resolve it.
Overall very happy with it.