I bought a sleeve to try out, the equivalent ball to the Callaway Z. For me, by playing this ball you are giving up about 10 yards off the tee and a small amount of spin.
The 100 credits reduction in cost in comparison to the Callaways makes this a very attractive alternative, given what I consider to be a small reduction in performance.
Of course for the very competitive, the human psyche will always err towards whatever they believe will give them the maximum opportunity to be competitive. Therefore this ball will not be the preferred ball of choice for the very best players. I wouldn't let that put you off however. If budget is a factor but you still want that bit of extra edge to your game, this ball is ideal for you. A good addition to the product range.
PS;
I just completed the Kiawah 18 Hole Ready Go playing the Srixon ball and the graphic below merely confirms my belief you can play this ball and be competitive :^)