buy both. i have found myself more recently liking the Z plastic, tends to not beat up as much as ESP. i plan to buy the z nuke this weekend because i've thrown my friends, which was significantly more stable than my 3 esp nukes at the same weight.
I've never been a fan of ESP plastic, but I love my ESP Nukes! The plastic is not as stiff as other discs I had in ESP. Due to this I was able to break them in quicker, thus making them less stable. Now this works for me, because they are just on the edge of my throwing abillity. Plus I was able to get them in liter weights (164 to 167). Helping me even more to be able to huck these things. I did buy a few 1st runs in Z plastic. So far they are OK imo, but not as long at this time.
Only for the ESP Nukes. They made a special run for the Memorial (they have the little radio active logo) The general concensious was that they were LESS stable than the 1st run ESP Nukes. Overall, most people like to grab up the 1st run discs. Reasoning behind it. Is that the molds have a closer tollerance. The longer the molds are used the more out of wack they get. Having said all that. The one constant you will find. Is that you could buy several of the same discs and they all might fly a little differnt. Heck, some people even say that color play a roll. Check out some of the posts on the Nuke..... The red Nukes are this....the green ones do that.....the blue ones etc...
Ya, there on this site. I think if you do a search and put "Z Nuke" you will pull up the posts. I like Champ as well, or at least I did. Dave D. from Innova responded to a post about "why Star plastic flies farther than Champ" The basic jist is that Star plastic tends to get you about 10 to 20 feet more distance than Champ plastic. So now all my drivers with a speed of "7" and up are Star plastic and all my mids are Champ plastic. Another twist is their Echo Star plastic. That tends to be the most overstable plastic out of them all. If you want to try some Champion type of plastic, but with a much better feel to it. Latitude 64's Opto plastic is awesome. IOM it's even better than Champion or Z plastic.