http://tropicalfruitforum.com/index.php?topic=25980.msg303738#msg303738This is a tasting report from Oscar of Fruitlovers.com
I thought it was interesting that the comparison was made between flavor or scarlet and red, but nothing about the Z4 being similar to the red.
I have been reading all the same message boards and part of me is hoping that the z4 that I have is different from the hundreds of red trees I have, but only time will tell. I can say that the immature tree, leaves and bark all look a lot like the red, but I'll just keep waiting. I wouldn't bet the farm on the Z4 variety in case it turns out to be a red by a different name or otherwise a dud.
My personal theory (which has no supporting evidence) is that it may be a selection from a choice red tree.
I have a handful of fruiting reds and can say for sure that some are much better than others. Some of the trees never get as sweet of fruits as others, some have fruits that are much sweeter and can be eater at earlier stages of ripeness. I have started to propagate my best trees to sell in my nursery.
Hope you find some more solid info in the future.