Honestly, in this day and age, any discrepancy from Chromium/WebKit is probably broken. But if we're talking about a few pixels' difference here and there, plenty of sites are more broken than that on every browser.
I have encountered a couple of (financial, natch) sites that insist on a Chromium-based browser in order to do vital operations like download statements. Switching browsers for those few exceptions is annoying, but not a deal-breaker (for me).
Have you tried a user-agent switcher? I think you can even set them up to always have a specific agent depending on the domain. Chances are, they don’t need chromium, they are just written by (even more than you’d think) incompetent people.
