Hey Izzi, thank you for the great review!
Are you using the Z2 with Windows OS, or Mac OS? I'm using Mac OS and I've read that there are problems with the J3 and Mac OS.
I'm looking to upgrade my iPod Touch (sound-wise it's not to my liking, but I love the touch screen and internet browsing) and iPod Video (not a fan of the click-wheel scrolling and the battery life is only ~2.5 hours)...I think the Z2 might just be it! Your review makes the Z2 sound really promising as I was originally looking at the J3 (until I heard about the Mac OS problems) or the D2 (until I heard about its sluggish performance).
How is the battery life on the Z2? I think the J3 will have the upper-hand on the battery life, but anything more than 12 hours of regular usage is really, quite plenty for me.
One last question...what color did you get?