We did a lot of testing on the new 2015 drivers and continue to test more every week. We finally tested the Cobra Fly Z and Fly Z+ and were pretty impressed. All testers used shafts fitted for them on each head using the Club Conex system. The ball used was the TaylorMade Tour Preferred X.
The Fly Z appears to have a slightly closed face at address so shot dispersion was a little more left of target. Launch angle was true to loft (13.8 launch angle for a 10.5 degree setting with an Angle of Attack of 0.2). The Fly Z+ launch was only slightly lower than the Fly Z with the weight in the forward position but it did drop spin by 250 rpm over the Fly Z. With the weight back in the Fly Z+, launch angle increased by 2 degrees and spin increased 350 rpm resulting in slightly less distance. I have played a Cobra ZL Encore for several seasons and it looks like the Fly Z+ will be next up on my list!
P.S. For more information and comparisons done by GolfWRX and MyGolfSpy, go to www.golfwrx.com and www.mygolfspy.com. A lot of opinions and results but it is obvious that you need to test the new drivers yourself with a knowledgeable clubfitter to determine what head and shaft combination works best for you!