I've got there muds with the Green Diamonds in 225/75R16 on my wife's '03 Suzuki Grand Vitara 4x4. Tread looks like the old Buckshot Mudders with the near continuous center zig-zag pattern and is consequently noticeably loud.
I'll give them this:
They perform great. When we got this thing it had some Bridgestone "all seasons" that looked mild for a Subaru. Replaced them around Christmas with these and we instantly noticed it was much better in the snow and inclimate weather. The Green Diamonds really do grip the road. I have my own siping knife and haven't even thought of siping these, they don't need it at all. My wife loves them and has never had a problem with them on the road or in the little offroad we've done with the "still-has-a-payment-family-truckster".
The poor side of things:
-HighTec took around a month to get them to us after repeatedly changing the arrival date. I ordered them before Thanksgiving '05 and they arrived the week before Xmas.
-Their phone answering staff was positively horrible. This lady I always talked to was everything from evasive to rude and lots in between. It's my understanding that she's no longer with them though. The guys I talk to remind me of myself at my own work. Don't call me, I'm a warehouse guy, not a salesman. I bet they can retread a tire well but their phone skills are lacking.
-The day after Christmas with 400 miles or so on them one had a tread failure. To HighTec's credit I simply took a picture, emailed it to them, and a week or so later received a new tire. Forget about any reimbursements for having to have the new tire mounted and balanced though. I brought it up during the phone call and in my email and both times it got completely ignored.
-My wife recently pointed out that one tire...and then I noticed another one...have portions of the tread where the tread doesn't appear to be adhering to the carcass. The tread doesn't feel loose but around the sidewall where the new meets old there's a section that is loose. It's not flapping but it's not attached like the rest either.
-I emailed them about these tires several months ago and got no reply.
I called on Monday and they gave me some emailing instructions which I followed on Tuesday and they said they'd get back to me about them and their opinions on the tires' conditions. Going on a week and no reply...
Do I like the tires performance? Yes.
Would I buy from them again? No.
For the money I spent for these I could have just saved a few more weeks and gotten some Kumho or Dunlop MT's from TireRack.com and probably never had ANY issues with them. Depending on what HighTec says about these tires...if they ever get back to me...I might just buy a new set of tires for it and toss these in the trash.