I'm using Google & it's been great.
Recently I migrated to iCloud from my MobileMe account. The only reason I'm just letting it sit unused, is the typical downtime & other issues that prevent it from living up to Apples Claims. It's hard to imagine that Apple still struggles with cloud services, yet perhaps by this time next year it will be improved.
Until then, I'm finding that the other free cloud services are very reliable & filling my needs quite nicely.