I was a fan of Vultr until, after Linode changed their $10 plan to have 2GB RAM, Vultr didn't match it. Beyond $5 it's no longer all that competitive. I guess the same couple be said of DO but I've never actually used them.
One nice thing DO and Vultr has is built-in support for FreeBSD (both) and Windows Server (Vultr). That said, I run OpenBSD, FreeBSD and SmartOS VMs on Linode through a manual install process. The only issue there is password resets through the web UI don't work and backups wouldn't work either.
Here is the guide I used to get FreeBSD working [0], and the others were easy to figure out from there.
But the Vultr $20 plan with 2GB RAM also has more bandwidth and disk space, and 2 CPU cores instead of 1. So I guess it depends on what you're looking for. I still think it's a great deal for what you get.
For standard plans, both Vultr and Linode have 1 CPU core at $10, both have 2 CPU cores at $20, and so on. Up to $80 a month, both companies have the same CPU count, but Linode has double the RAM. Vultr's bandwidth starts out a bit better but is surpassed by Linode as the price tiers increase. Linode's disk space is also a bit more generous.
Were it not for Vultr's current promotion matching the first $100 of funds that new customers put in their accounts, I would think that they seem uninterested in competing.
