I don’t have answers to your questions, but might suggest you read this article and also the longer piece it links to before committing to Backblaze.
This had a good airing in this Tidbits thread.
It did cause me to think hard about staying with Bacblaze, and I even started a free trial of CrashPlan. But subsequent discussion in that thread put the Morpheus report in clearer context, and I decided to stay with Backblaze.