I like Digital Ocean. I use it to host cronkd.com. I don’t have firsthand experience with the other options.
A coworker “Co D” (who’s far more experience than myself) today remarked that Linode and Vultr are better than Digital Ocean. Asked why, he responded: price, stability history, disk I/O performance, cpu specs, memory performance. Digital Ocean uses OpenVZ usually which means you’re sharing cpu resources. Linode/Vulture use KVM/Xen which give dedicated cpu time.
Another coworker “Co T”, the one with whom I partner on hobby project cronkd.com, followed up explaining that he has been moving projects from Digital Ocean to Linode.
Co D recommends Cultr if you’re doing a BSD or uncommon distro. Linode if you’re doing a common distro (deb, centos, ubuntu, etc). He’s been hosting various servers for 15 years.
Co D also commented that freebsd is the best server OS and that he’s biased and in the minority in that opinion. Hi CPS advice is good, his OS choice is questionable.