There was, at launch - they were terrible, didn't work properly, had a ton of downtime, etc. It got a reputation for being a slow, useless, unreliable service, and while the service got much better (I've been using it almost since its inception), its reputation never truly recovered.
They were terrible about merging conflicts, made them unusable to me. Hope Apple have worked out how to do this better now...
Truth is on the cloud.
That does not solve the problem, as devices can go offline. If they come back with a change from an old version you still have to deal with a conflict.