I currently have most of my stuff split between Digital Ocean and Linode. So if I had to move quickly, it'd be Digital Ocean.

I'm going to be kicking the tires on Hetzner and Vultr soon, because DO is not a super satisfying backup plan for me.

I've used Azure enough to get spun up quickly there, but that would be an unhappy upward adjustment on my budget or an unhappy downward adjustment on the performance I expect.