I've used BitBucket as a solo dev working on personal projects, a solo consultant, and an employee on a team. It's pretty mediocre, especially if you look beyond its integration with the rest of the Atlassian ecosystem.

The number of times I've wanted to search a repo for something only to have to clone it and search in my IDE is staggering.

Same for me - lack of searching kills me every time!

You might want to look into https://github.com/etsy/hound if you ever want to search. I found this superior to Github as well if I want to find all repos that reference something.

The repo migration functionality is also super flimsy.

Yeah, but GitHub got me early on before I cared about private repos, and honestly I was just too lazy to move stuff over. They also win me over with integrations, though I'm sure BitBucket has a similarly expansive set now. Had I ever gone full Atlassian, I'd have switched, but never wanted to add Jira to my life badly enough (though when I was seriously working on a project with a friend, I considered it).