You can see full review at LeonardReview.com - SiteSync Review. But before that, let me ask you a quick question: What will you do if your site gets hacked?
Half of my friends answered that they will restore their data from a backup file. Some would event try to find the security vulnerability and fix it. They are right, get your website back online immediately is the first priority. And if you can, try to fix your system, scan it to find any problem could be still lying around (and to prevent any backdoor that the hacker had left behind for further attack).
The problem is, the other half of my friends know nothing about backup. Some don't even know what is a backup. I know, they'll be in BIG trouble once their sites get hacked or just some random data loss.
And because they know almost nothing about backup, I can't just teach them everything from zero. It's easy for people who are using shared hosting, they often provide cPanel and you can generate automatically backup from there. Things get more complicated when you use VPS, especially when you run a self-managed VPS. If you're in the same situation, I suggest you ask your VPS provider if they have daily backup feature.
From my point of view, the best scenario is that you can backup everything daily. But, manually backup is a boring task which you can accidentally make a mistake without even notice. Not to mention you could have plenty of sites need to be backed up. Another acceptable option is to get your site backed up automatically with 3rd party software.
So why did I choose SiteSync? The most important reason is its onetime fee. You only need to pay $27 for 5 sites and 10GB storage. This plan is suited for almost everyone's needs. If you need to backup a lot of websites, you can take the elite plan with $37 for 50 sites and 50GB storage.
The next reason is its simple backup process.
Backup: You log in, pick your site, choose how often you want to back up, confirm, done.
Restore: You log in, pick your site, choose which file you want to restore, confirm, done.
The last reason, this software is a part of a large platform name SyncManager with many potential choices such as TubeSync, VimeoSync, WistiaSync, etc. And they're still working to bring more software into SyncManager.
No matter which way you choose, the most important thing is back up your sites often, and store your backup files in a safe place.
P/S: One of my friends try to upload his backup files to Dropbox. Ok, hackers needed to bypass all the firewall and DDoS protection before they can touch his website. Now they can download all his site with one password. Don't ever try this.