My big argument against carbon wheels with rim brakes is mostly just the braking. I still have 1 road bike with carbon wheels and rim brakes...it's not my "daily driver" bike so it caught me off-guard when I took it out for a ride this winter, and it started raining while I was on a descent. I was able to just dry the brakes enough to slow down for a hairpin turn. After that, I stopped riding it unless the roads were perfectly dry....I've got disc-brake bikes that I'll ride in the rain/snow.
Even in dry weather, I can't say the braking performance is especially good. I'll say it's merely tolerable and not even comparable to my disc brake bikes or even my rim brake bike with alloy hoops.
As far as tire clearance, it hasn't been a big issue for me. It's tight, but I'm able to run 28mm tires on that bike. I'm up to 30mm wide tires on the back of my disc brake bikes, but 28mm works ok for me.