Tools are definitely important, however proficiency with those tools and most importantly, proficiency with the language are the largest determining factors. It takes months (if not years) to get to the point where you're really comfortable in a new language and can crank out volumes of code relatively quickly.
If you made me write with Eclipse, I'd probably be horribly inefficient. It's not that Eclipse is a bad tool, it's just that it lends itself to languages that I'm not super fond of writing in (ie. Java, ActionScript, etc.) and it's much different than the way I'm used to working (with vi, git and a command line). If you transplant a C# programmer into the vi and Python world, they'll usually run away screaming. Neither is better, they're just different.
If you made me write with Eclipse, I'd probably be horribly inefficient. It's not that Eclipse is a bad tool, it's just that it lends itself to languages that I'm not super fond of writing in (ie. Java, ActionScript, etc.) and it's much different than the way I'm used to working (with vi, git and a command line). If you transplant a C# programmer into the vi and Python world, they'll usually run away screaming. Neither is better, they're just different.