I had a chance to hit with these. For reference, my regular racquets are Head Graphene Touch Prestige Pro, 345gm, 31.0cm balance, 320 SW, PP Black Force at 45#.
I hit with the UP 16x19 at 335gm, 31.0cm balance, guessing around 315 SW, PP Black Force at 45#.
After the first couple of shots, my thought was that this racquet is equipment, not a toy. Many racquets feel "cheap/hollow", like a toy. Not this. The racquet is SOLID. The sound of this racquet is excellent, a nicely muted "thwack".
As far as flex, this feels pretty close to my PP, except the PP flexes at the throat. The UP to me feels like the flex is the same across the whole racquet, very UNIFORM flex. It is not a stiff racquet, but is also not a noodle. There is plenty of power in this frame.
Launch angle is a little higher than the PP, a little more spin. For me this is good.
So far I am very optimistic about this racquet. Next is to add a little weight at 12 o'clock to bring the SW up, then add weight at the tail to get back to 31cm balance.
Will report back after those adjustments. So far, so good.