I've been using Loopcloud, Drum and Play in CbB the last few days and I love the way Loopcloud integrates. I'm chopping and key shifting samples in Loopcloud and importing them into CbB. Even for someone not experienced with working with loops like me it's remarkably easy. You can export patterns from Drum too then groove clip loop them.
I've just got the free account as I couldn't justify paying for it but even that has free samples and free points to buy a small number of samples with.