You might want to check out vultr.com. They don't directly support OpenBSD, but allow you to install an OS an a VM instance with an ISO image, either by you supplying it or they'll pull it for you through an ftp or http link. Their pricing is similar to DO.

I managed to get an instance running without too much trouble.

(I do not work for vultr, or affiliated in any way).

I use vultr too and find them pretty good if very slightly pricey

Is there anything like http://serverbear.com/compare/vps that lets you browse OS's offered by various providers?

Also wondering how reliable Vultr's been for you guys.