In the "Where DigitalOcean Beats Lightsail" section, you might add that the OS selection on Lightsail is extremely limited. I believe you can currently only choose Amazon Linux or Ubuntu 16.04 LTS.
Which is a little odd as you can get Windows running on an EC2 instance (t1.micro) for $10.95/month. Although maybe the margins on Lightsail are too thin so Amazon doesn't want to pay Microsoft's licensing fees.
And before someone whines about Windows, keep in mind Windows Server 2016 now installs headless by default and will run on 512 MB of RAM (which is what the $5 Lightsail offering has).
Keeps the pricing down, since you're the one responsible for licenses.
The way Microsoft licenses Windows Server to Azure/AWS/etc is completely different to how they license it to you or I, and the pricing is hard to compete against at the lower ends.