What does everyone use? I've heard good things about carbon copy cloner.
You want to have a multi-tiered versioning strategy covering the various scenarios in which you need "backup", as well as disaster recovery and business continuity.
So think about your specific needs in those categories.
My strategy is thus:
Backup:
I use TimeMachine to my NAS as the primary versioning backup. Covers the "oh sht I deleted a file I didn't mean to" as well as "hey I overwrote this document and need a prior version" scenarios.
Disaster Recovery:
iDrive (BackBlaze also good) for cloud backup - covers the fire/flood/burglary scenarios in which I lose my computer and my NAS. Also covers a failed Time Machine restore scenario. I use a complex private key to encrypt it, and that key is retained in 1Password with the vault synced across devices via iCloud.
Periodically I'll also use CCC to create an image backup that'd stored offsite yet accessible. Meant mostly as a secondary offline version "just in case" as well as a failsafe if the other methods were to fail.
Business Continuity:
I don't use my mac for work, so I don't have substantial needs in this category - ordering a replacement machine and using an old windows laptop or my rMB 12 in the interim is sufficient - I don't need bootable-clone level disaster recovery speed.