We did a whole house in LED lights for a customer as the manufacturer was one of her clients. They were difficult to work with (some would not work and had to be replaced from the git-go) and when they do die, the whole thing has to be replaced. The light that they provide has a more narrow cone to it and it takes far more lights to cover an entire room than the traditional recessed. We also could not get any decent pictures after we completed the project - we even hired a photographer and his pictures were as bad as ours. The light is just strange.

CFLs brighten slowly, and some people find it annoying to wait for them to fully turn on. Not necessarily a reason not to use them (we are putting them in our kitchen now), but i do know someone who switched them out for LEDs after a few months because he couldn't stand it.

aeb - what type of canister are you using? are you using a dimmer?

We are using 4 inch utilitech new construction airtight in the kitchen and 6 inch commercial electric in other rooms. No dimmers planned right now.