So I test rode a Cervelo Soloist (105 build) and a Specialized Aethos (Pro Ultegra di2 build) over the weekend. Both bikes felt really nice, though, to my surprise, neither felt as "alive" as my lowly $300 Lemond Zurich. Steel is very much real*. The Aethos was probably 16lbs or less and it felt very quick to accelerate, but the Soloist was no slouch and seem to maintain speed better. Both bikes felt very smooth and comfortable. I think I would enjoy the aero benefits of the Soloist more on longer rides over the lower weight of the Aethos because I'm more of a Rouleur/Puncheur type rider than a Climber. Also everyone and their dog has an Aethos in San Francisco...One thing that surprised me is that the Soloist is actually heavier than my CAAD12. Part of that is in the components (in particular disc vs rim brakes) but the frame is only like 200g lighter also.
One important thing I learned is that I'm not a 54cm frame size. I've bought bikes in the size for close to a decade now, but after riding my 55cm Zurich and noticing how natural it felt. I started to question it. Both bikes I tested were in 56cm and they felt just correct. I rode my 54cm CAAD12 today and I realized how weird it feels - I have a really hard time holding a more aerodynamic position because I feel super scrunched up, my quads are doing all of the work (because I'm too far forward) and I'm constantly pushing myself backwards on the saddle (which is already slammed back almost as far as it will go without an offset post) in a semi-successful quest for more glute power. My size medium Soma riff feels comically small even with a dumb looking 120mm stem. My size medium Ribble has an even more honking long 140mm stem so it feels pretty good. I think I might be a large boi.
*Part of me wonders if a high-end and/or custom steel or Ti bike would suit me better than a carbon frame for just this reason. However, I would really like to experience the aero and compliance benefits of a carbon bike.
So all in all, I'm likely going to get the Soloist. I wish I could get a 105 build without wheels, because the stock ones aren't great, but I don't want to pay an extra $1500 for the "race" build, when I could get a decent set of carbon hoops for around $1000 and the rest of the build is totally fine for me. I'll probably try to sell the wheels.
I will probably end up offloading the Cannondale and the Soma while keeping the Lemond and Ribble - a 4 to 3 consolidation.