When I say modern, I mean away from the classic box beam type of feel you would find in an older Dunlop, Wilson or Prince racquet. For instance, Six.One 95 has a classic box beam feel to it, whereas a Blade 98 has a more modern feel to it. The difference for me is in the way the frame responds. In the Blade/SIx.One comparison, the Blade feels faster and snappier in its response whereas the Six.One flexes in a more classic, relaxed way. I'm not talking about stiffness alone, more in how the frame feels as it flexes, where it flexes and the feel of where the racquet face has flexed to (how far it is still laid back) as the ball leaves the strings. We are getting pretty deep into racquet feel here, and I don't want to make this sound confusing.
However, if you really want to confuse the issue, hit the Slaz Pro Braided -- it's almost as if it combines both the classic and modern feel into one, and that's part of what makes it a great racquet IMO, but I digress . . .
The new Dunlops feel like they are snapping back faster and feel more responsive when I hit them compared to the older ones. I thought comfort was just fine from the new racquets and power improved. I did not find easy access to depth from the existing Bio 300. On the plus side, it was tough to miss with it as I could take a full swing on almost everything. With the M 3.0, I was getting some added zing.