I use to always use the Scalemaster II rotometer, but after miles and miles of takeoffs its worn out and is less then reliable. I liked the position of the count buttons and +k (adder) button. I could move through a take off pretty efficient using the thumb and forefinger to operate each button while rolling. They've discontinued them now although I still see them online for sale but everytime I've tried to order one I end up with a Scale Master Pro XE which is the replacement and it doesn't even have a count button. I just got a scalex that I'm working with now but the count and add button or on the same side so it seems cumbersome. What do you guys use for a digital rotometer?