My opinion...I know that there has been alot of talk and even JP articles about Thornbird or thorntirds as some call it. Myself I run 33x12.50 Thornbirds. I have had them for three years. I have wheeled,  drove the Jeep on highways to wheeling trips and back. Rocks, mud, sand, dirt they have done the job. We have a variety of tires being used in our club and the Thornbirds have performed as well if not better in some cases then most. They do not suck as bad as some think. After 3 years I still have 3/4 of the tread.

The bad side... if you dont like a loud tire then dont buy them. They suck on wet pavement just like any other tire. I have found that they are not real good in heavy light snow, other then that they look awesome and they do good on the trails. They are a little heavy as well. Interco will not stop making them because they are selling alot of them I am sure.

Would I buy them again....maybe I am looking at the Maxxis creepy crawlers right now. Not made in the USA...I dont like that but WOW they are bad  

i loved mine on my 84 blazer, 33's as you, they did everything flawless, BUT LIGHT SNOW AND ICE, IS A NO NO WITH THESE. but deep snow with ease. i loved the mud these flung, were talking 30 foot roosters man. as i live in northen MN, and have to travel on snow and ice 4 months a year, id say not as a daily driver for me. but as a mud tire, sand tire, and terrain i give a A+ .  the only other problem i had was with minor dryrot, or cracking above the bead, it never leaked, but there was a small crack all the way around.  

Go with IROKs and you will notice a substantial differance in mud and snow traction.