I have never used them (but haven't raced).

When I am on a rough trail going up or down hill I always use drops. Otherwise I typically use hoods.

I just don't feel like I have the control and balance and shock aborbing capability I need when on the top bars. I have tried to force myself to use bar tops, but when it gets technical I just fall back into the drops.

Maybe it is my bike set up. My handlebar tops are lower than the saddle, but not 'road bike' crazy low, but I like it that way for trail riding and commuting.

Al