I don't have any history with Head racquets (except the Arthur Ashe model in the 70s) except for the Extreme Pro 2.0. My previous racquets were Wilson Classic 6.1 and 2012 Six-One 95 BLX and 2012 BLX Pro Open.
I really like the Extreme, as it plays lighter than it is spec'd, as well as less stiff than the RA numbers suggest (probably due to the new grommets). It definitely feels much lighter than the Six-One BLX and similar in stiffness, despite the BLX being spec'd much softer. I find it very forgiving as well, more than the Steam 99S that I've been demo-ing, as it is quite stable in off-center hits that still produce a good penetrating shot.
I hit with a lot of topspin on both sides, plus a slice backhand and serve. The Extreme allows for lots of spin, but it is easy for me to flatten out when I want power. Using a textured poly, like Solinco Tour Bite, can produce some crazy spin with this racquet.
As you can see, I think it is a great racquet. I tried it after reading the TW playtest and agree with everything in their reviews.