If you can share what you are using right now and why you've decided to use it. That would be helpful. Thanks.
Side project - Rackspace. I've used Rackspace on various projects over the years and have grown to like it. More robust then Digital Ocean and not as complex to manage as AWS. It fits right in the middle IMO. For me, it's just enough. Spin up new servers relatively quickly; a CDN, a load balancer, cloud DB, Mailgun proximity - it has everything a growing site needs again, without all the complexity of AWS.
Freelance projects that find me on their own - Digital Ocean. Everything a mom and pop shop needs without the costs of Rackspace. Or 1and1.com - can be slightly cheaper then DO.
Freelance projects given to me by freelance companies - whatever they use. A Small Orange is one, one has used often. Most everyone runs Plesk or some variant of it so usually never a big deal to get up and running quickly.
When the client doesn't care about $$: aws/heroku.
When I don't need raw performance: https://www.webfaction.com/?aid=9281 (the best/unique vps/shared hosting available)