I Love Crate-Tranning Done Correctly
I have used a crate on both of my dogs and it makes them, in my opinion, all around better pooches. They are comfortable being in "there space" when I have to be gone or must leave them with a sitter(usually my MOM).
I do not feel that the crate should EVER be used for punishment and that the dog should always know that it is a safe and loving place to be.
With my Boston Terrier, We used the crate when we were from him for a few hours and the first few months at night. Once he was eating fewer times per day and sleeping all night we moved him to his "big boy bed". We never had any problems with potty tranning either but NEVER used the crate as punishment if he did have an accident.
With baby #2, An American Bulldog we are just starting. He LOVE's his crate! I am also a BIG fan of scheduled feeding and potty breakes. My dog's are like clockwork! The Crate becomes like a safehaven for the dog's once they learn what it is for. We have only had our AB for a few weeks so he is still sleeping in there. He always goes to his crate at 10 pm ready for bed after his last snack of carrot and Peanut Butter and his last sip of water.
It also makes it great when I have to leave them with a sitter or the kennel that we leave them at. They always have their crates so that they can really fell like they are at home!