I have been fitted in a more upright position, and I feel like I have a lot more power than I did before. So now I pose the opposite question from before. Why go low? Is it just for aerodynamics?
One advantage that I have found besides the extra power (now that my handlebars are higher), is that when I do come out of my saddle to sprint or climb I have more stability, because I no longer have to crouch over when Im pushing hard on my pedals.
I am so confused now...
The advantage of having a 'long' setup rather than a low setup is that you have more room to sprint and use your upper body. Loads of guys want to have their bars as low as possible to mimic what tall pro riders look like, but have a look at guys like Cancellara and in particular, Cavendish. They have a longer setup allowing them to stretch out rather then rounding their backs to reach down to bars that are lower, but closer.
A while ago I was on the path to have the bars as low as possible, but the lower they went, the short the stem I needed. End result was a rounded back, loss of power and lower back pain.
Up came the bars, longer stem went on and now I have a flat back, am just as aero (even though initially it feels too high) and plenty of room to sprint and in that regards, I found the 200W that went missing in my sprint kick.
My point is, you can bring the bars up and get your power back, but by allowing yourself a longer reach, you will give yourself that space to get brutal with the thing.