Kinesis looks good for data entry and such keyboard-only activities, but otherwise, when one hand is using a mouse, I don't think it is comfortable. Any experiences?
I have used a kinesis for 12+ years as my main keyboard.
I'm not fully sure what you are asking -- I would guess you're referring to the fact that it's harder than usual to type with one hand and mouse with the other, because you have to reach across to the other side of the keyboard?
If that's what you're asking, I agree -- but I consider it a good thing :). I found that the kinesis helped me focus on touch-typing more and relying more on keyboard shortcuts to navigate; it's a bit of a learning curve but ultimately worth it for ergonomics and speed.
In case of the browser, I've augmented it with the Vimium add-on. I've gotten so used to touch-typing that I'm annoyed when I have to reach for the mouse, even despite the inherent delay for reading Vimium's label on a link. That's why I want a touchpad in quick reach. And also for the two-finger scroll with its analog sensitivity.
This keyboard-reliance has led me to another observation, that web devs don't test keyboard scroll on their sites.