I prefer CK one. I don't like either that much to be honest. Chrome has a metallic note that is just too much for me, I've tried to overlook it but it's impossible! Ck one is a decent fragrance, but nothing special.
For some reason my nose changed how I perceive Chrome. It happened very suddenly, but Chrome as I originally smelled it would be the winner for me. It is the fragrance that turned me into a fumehead...
I often wonder if people who love this fragrance smell it as I once did -while its detractors smell it as I do now.
I carry these two on business trips; they're inoffensive and pleasant to a fault. Of the two, I prefer Chrome because the musk drydown in CK One seems out of place for the occasions to which I wear it.
Chrome has a very brash metallic note and that very note lasts for a long time and annoys the hell out of me. I don't remember CK One having impressed me so much either, but if it were an either/or choice, I'd go with CK One.
It isn't a terribly good idea to blind buy chrome. You may end up with a full bottle of something that you cannot tolerate.