I don't really know the difference, I've only ever used Snapper. It comes preconfigured on SuSE Tumbleweed, and I've set it up manually on those machines I have that don't run Tumbleweed.

I like Snapper because once set up it basically just does its thing on its own, and it's super easy to use. I can access the snapshots from the boot menu so if something goes awry I can just boot into a previous system configuration.

If you already use Timeshift and you're happy with it I don't really see why you'd switch.