OK, now I have a few minutes. I've done a ton of research and have a fair amount of experience with this since I've lived on various continents and for a while was keeping the majority of my data in the cloud (much of it encrypted). Feel free to ask questions.
Bitcasa: STAY AWAY. Their speeds are OK, features are pretty good (stream media from their website or apps), prices are bad, but business practices suck a$$ (They made promises not to raise prices, encouraged people to upload all their stuff; raised prices, but told existing customers "don't worry, you're grandfathered"; then gave 'grandfathered' customers less than 30 days to get their stuff out, pay 10x price, or get deleted; was bad enough that there are lawsuits now)
Dropbox: most mature and stable of all the clients I've used, but expensive; quite fast. Uses block level syncing, so doesn't sync the whole file..only the part that's changed. Useful if you keep Truecrypt containers, etc. in the cloud. I now only use their free account, and mainly for the files that need that type of sync.
Onedrive: copious amounts of space, pricing is phenomenal, speed is okay. Client isn't as full-featured as others. Nor as stable in some situations (for example, if you run out of disk space in crashes and corrupts the cache so it has to start over from scratch). Has a nice feature where you can select files to keep only in the cloud but still has placeholders locally (this probably will change in next Win version). Takes a bit longer to sync across machines (for example, I have a torrent folder in Dropbox where I drop in .torrent files and my server watches that folder to auto start the download; takes minutes with Dropbox, but anywhere from 30-120 mins with OneDrive), but this is a special usage case.
Crashplan: use it for its unlimited backup on up to 10 machines, reasonably fast if you do the tweak to disable client-side duplication scanning. Have all my machines, and my parents and sister backing up to it. Pretty cheap for that. But you can't stream off of it like you could Bitcasa. I'm hoping they will add that feature, but honestly I've heard it was one of the features that attracted the wrong kind of crowd to Bitcasa. IMHO best for cloud backup, but need something else for cloud storage.