The main problem with the device is that it uses a single core ARM processor which is underpowered for many tasks.
But as of last week, you can now overclock it to 1GHz without voiding the warranty. Now your DIY drone will have more computational mojo!
From their site:
We’ve been doing a lot of work to understand the impact of voltage and temperature on lifetime, and are now able to offer a “turbo mode”, which dynamically enables overclock and overvolt under the control of a cpufreq driver, without affecting your warranty. We are happy that the combination of only applying turbo when busy, and limiting turbo when the BCM2835′s internal temperature reaches 85°C, means there will be no measurable reduction in the lifetime of your Raspberry Pi.