I love Google Domains. Their pricing is consistent, I trust them, they use the same billing as on the rest of your Google account, they have nice nameservers and easy DNS settings, and you can transfer domains easily from account to account.

easyname.com I worked there for 2 years.

I am on native German euserv.com, using several of their services combined, and have been since they did beta tests for VServers years ago. I have never had real trouble, the worst being a server failing due to its PSU. They resolved the problem within the hour at 4AM in the morning, which is just what I expect from a good provider, so I stay with them.

Only for my .io domains, I have to use GoDaddy nameservers. I don't particularly like GoDaddy (rather an image thing, though), however I never really bothered as I only use their free services.

GoDaddy. Because I have for years.

GoDaddy until they only switched to allowing offers to NEW services. I now use HOVER (Tucows) for new registrations.