felix5
Actually DB is not that much bigger than logitech. I had logitech BJ58 for gaming very long time and now have DB (albeit now in exchange due to a faulty button). Logitech is slightly shorter than DB, but it's also higher, so overall is's a tossup. It's just a matter of what you prefer - smaller height or smaller length. Logitech has shorter click travel, that might be important in some games, but I personally prefer DB click, it's much smoother and more pleasant - after all I spend a lot more time in windows than gaming. If you truly want mouse as close to your logitech is possible then viper fits all criteria, it's shorter than DB and height is closer to the logitech. I cannot comment on the tracking issues though as I never had one.
You can search for reviews, I'm sure I've seen one review which had photos of DB right against MX300, that might give you an idea of the size.