I've recently switched over from Callaway's Steelhead X-14 cavity backs to the Titleist 690 MB blades. I notice a really "BIG" improvement in my swing. 9 out of 10 shots are dead straight to very slight draw, which is the trajectory I aim for every time.

Withy my Callaways, I'd get a more pronounced draw/hook. I think this is primarily due to the offset on the clubs. The Callaways were great when I was a beginner but as I progressed further into the game, I learned more on the mechanics of the swing and realized how the shaft, the clubhead, and the hands work in producing the proper swing path. Bottom line is, if you "know" how to swing the right way, blades are the way to go. They feel lighter and are very accurate.

As someone mentioned earlier, the golf swing can only be taught so much, the rest of the knowledge and the ability to produce good shots comes from within - practising the "correct" way and getting the "feel".