I've used both Crashplan and Backblaze personally but found both pieces of software to be painfully resource intensive, particularly in CPU usage on a rMBP with good specs. (I should not be able to know your software is running by the slowness it causes me in the middle of development when I have it set on the "optimal" settings.)

IMO neither is really better than the other. I feel like a good complete remote personal backup solution for someone with multiple drives [1] doesn't exist today.

[1]: Read someone with an SSD MacBook and years of data accumulated from other machines that don't fit on the built-in SSD.