Turbo is great tool for experimentation. Very convenient for determining limits of your hardware. Be advised however, that once in Windows, the system is more tolerant of OC's. Just because you have a stable OC w/ Turbo does not mean you will be able to satisfactorily boot to those settings. I find it very useful for "getting into the ballpark" so to speak. If I had to enter BIOS and reboot every time I wanted to crank things up a hair, I'd waste a lot of time.
When I build anew box for someone, generally they are real anxious to bring the box home and start fragging their buds. With just BIOS editing, I'd be at it for hours. With the Windows tools, I can zero into the neighborhood so to speak and then do the final tweaking via the BIOS.