For someone's personal project I'm not sure why anyone would choose to avoid the new shiny features of their preferred browser given that those features will wind up in the others eventually. It was the same situation with HTML5 where devs jumped at the ability to write code that was forward compatible and to hell with any 'legacy' browser that wasn't modern enough.
For community OSS projects I would never expect them to spend time mucking about with cross browser compatibility given that they will be eventually consistent.
For community OSS projects I would never expect them to spend time mucking about with cross browser compatibility given that they will be eventually consistent.