I have both and can say the big z for me is very so slightly more US. The mold "dome" looks the same as does the rim. I feel that the slight US is the same between a heat in either z and x plastic. The big z thrasher is an opaque plastic that looks and feels closer to an esp plastic mixed with z plastic. I have found that any difference between the two can be corrected with a slight change in release angle so for me it flies the same to me.
I use a 170g heat in x plastic for most of my drives and get nice US long glide to about 300 to 325. If I try and throw a heat any harder or into a slight head wind it turns over hard and chashes or never stops going US. I love the heat and find it very predictable and pull it out of my bag 90% of the time until the thrasher came out this summer.
I am 41 years young and as much as I would love to tell you I can throw a 400 foot bomb I don't have the arm speed to do that, and I doubt most my age do if we are beginning truthful. So when they released the thasher it sounded like it was made for guys like me.
I picked up one of the first run thrasher's in 168g and my first hard drive with it was a slightly more stable version of my 170g heat in z plastic. This gave me the confidence to throw it a little harder than I would a heat and or even into a light head wind 5 to 7mph and know it would fly straight and come back in the case of head wind. For me throwing it hard and flat nets me around 350 very consistently or 300 to 325 into a slight head wind.
So in closing, the thrasher is now on par with what I pull for my drive, 50% heat and 50% thrasher and whether I'm going all out distance or need a little more control in no wind.
I think discraft will have a real winner on its hands if it drops some thrasher's in x or esp plastic next year.
