I’ve been using Vultr for nearly a year, granted it is only a sandbox running Discourse, thus no traffic, no real users, but it gets the job done and hasn’t had any issues what-so-ever (apart from running low on disk space from time to time).
To my knowledge, it hasn’t gone down once, not that I would care though.
For those waiting live sites they can depend on, I can’t say I wouldn’t recommend Vultr, but I also have not put it through any real tests, so take it for what you will. I will however say, DO gets a lot of love from the people who depend on it, and I mean, they depend on it. It isn’t just a sandbox for them, it is their live system.
I will add one to NEVER EVER USE, CloudAtCost. Don’t bother, not even for a sandbox. I attempted them for a short while, just curiousity more than anything, and I spent more time tearing down the server and rebuilding it, so I could bring it back online than I spent actually using it for a sandbox. Needless to say, I didn’t stick with it for very long.