Soldato
I just like the eye test. If I think something looks cool, I'm in. I like the Tarmac SL8 not because I think it'll make me faster than the ultimate, it just looks cooler than my ultimate. At the speeds I ride the difference could be put down to better tyres.
100%
I think weight probably comes into it on certain things more than others too. From posts from more knowledgeable folk on here. Saving 500g from a better wheelset will be more noticeable vs 500g from frame weight.
Ultimately, there's people cycling all around the world with bikes loaded to the brim weighing 40kg cycling >100km every day on bike packing trips. They're using relatively budget basic bikes with cable gearing and rim brakes and could probably wipe the floor with many of us just because of their volume. There was a Cade Media podcast with a guy who cycled round South Africa. He said he entered a race and won (i think, if not won then certainly very highly placed) just because he'd spent months cycling 1000km a week with a heavy ass bike, so when he removed all his bags etc the bike felt like a feather!