I was recently faced with the same dilemma. I really like the H10 (without the spring) and used it wore to the point that it couldn't be fixed. That being said, when it came time to replace it, I went with a micro motor instead. My old hand piece is still good enough to polish and grind and that sort of thing it just lets go of the bur if there is any tension. I also have used and really like the H28 but I don't like that it's not quickchange.
Instead of replacing my hand piece, though, for not too much more I got a refurbished micromotor and I absolutely love it. I love my Foredom, but nothing beats the micromotor for setting stones, in my opinion. Also it has cruise control. My only problem with the micromotor was, for the first week or so, overcoming the impulse to drop it to the side...that's a good way to ruin a hand piece.