I use DO as well for a number of different things, both production and development. It's worth noting that they just received a $34.5M round to grow. I've had a few support issues, mostly migrating servers to another account (for clients), and the team has always been very quick to respond.
I've tried other services too for low end servers, all for testing. I tried RamNode and a couple of other low end providers... RamNode was incredibly flakey and the others ran out of space. DO is the only provider I've found that scales to a comparable level of an EC2-like provider.
One downside is private networking. Right now it is limited to DO's NY datacenter, and technically it makes your server available to any other server on the network (something they're working on). With a little creativity (in firewalls), it is still possible to setup a private cloud without using up ridiculous bandwidth, but you're restricted to one data center. So, for really large globally distributed systems, I don't think DO is a good fit - but for small to mid size stuff I choose it every time.