I've only used them a few times,  but they perform very well.  The air flow was low, so I can see how they might be hot on a summer ride, but that is a few months off.  For a winter ride in 55 degree weather, I didn't need shoe covers, but I can see how at 45 degrees they would make life more comfortable.

The do run a little small, so I ordered one European size larger as other reviews had suggested.  They fit perfectly.  I wear a 42 in Ecco and Birk, so I got a 43 and they were dead on.

I have Look Keo cleats on them pushed all the way forward and they fell like they are positioned well.