I just completed 8 hours of playing with my Z Speed 3u strung at 23lbs with Zymax 65, my notes would be as follows:
Great paint job - vibrant!!
I felt my VT80 swings faster than the Zspeed when testing it on drive shots
It's not great at changing direction in doubles or quick enough to defend against big smashes.
Clears back hand or forehand are easy enough
Drop shots are accurate
Control is average overall though
Smashes are very good, better than the ZF for me
In conclusions I found it better to play singles with but not quick enough to play a reasonably quick (intermediate/advanced) doubles game with. The points gained through heavy smashes are equaled through the points lost from poor defence (millisecond differences count here) or reaction times. It is however one of the easiest Z's to just pick up and play with, ultimately for me, the VT80 is the pick of the Yonex range and still the better all round racket.