It allows control of power usage, throttling of CPU voltage and multiplier, hard drive speed (for power and noise), ACPI control (extremely handy - it let me know my laptop's CPU hit 205.15F (thats like... 80C?) and told me it would shutdown in 15 seconds to keep damage from occurring.
It gives you graphs for CPU usage, CPU temp, HDD temp, battery level, battery charge level (as in how much power is being used/added to the battery), etc etc.
It does much more than what Windows (or Ubuntu) does already.