Tire wear and cost
I did lots of research on these and the Mefo's. First and foremost - take internet research with a grain of salt! I don't believe everything I see on the net. That being said, many have posted that they have gotten exceptional mileage from both the Heidenau's and Mefo's. Several have said they've gotten 8K miles or more. I guess I'll find out the hard way. Where I live, anything offroad is super-soft sugar sand (2 miles from the Gulf coast). I have a hard time in it but it is very easy on tires. (My kid leaves me behind with his XR80.....)
As for the price, yes, they are more than many but not near as expensive as the Mefos, Metzlers or Continentals I was considering. I had them at my door for around $220 including shipping. If I get over 8K miles out of them, I'll consider them a good deal.
I balanced them and during a short ride afterwards I noted that there was no shake or vibration on the street. They were a little noisy, but not too bad. I don't mind a little noise because I know it is unavoidable with an agressive dirt tire.