I have 2 pairs of the 3-eyelet style like Chuck's. The first pair fits good with a lightweight pair of wool socks. I decided I liked them so well that I ordered another pair a half size larger so that I could wear them with a thicker sock for cold weather. They are extremely comfortable; I wore mine last year when backpacking for elk - worked great. I have a pair of slip-on "Totes" rubber overshoes for when the ground is real muddy or snowy and a pair of "Neos" high-top overshoes if the snow is deeper.
I have some of the tire crumbs, also, but have not tried them on the Arrow mocs. I used them on a cheap pair of Ataska mocs I had a couple of years ago, but it does tend to stiffen the sole a little bit and you lose some ground feel. Once you get used to the great ground feel you won't want to give it up. I've scrambled around in blackberry brambles and other brushy terrain and not had a problem with anything punching through the leather - It's pretty thick and tough.
I have also gone the Russell route - I have 2 pairs of them. I think the Arrows are a better value, but I still use the Russell occasionally when I need a little more traction (I have the Newporter sole on one of the Russells). For overall comfort and everyday wear I don't believe you can beat the Arrows. I measured very carefully per the Russell instructions and they still came out too large, so I have to use the thickest wool sock I have and even then they are a little loose in the heel area. Considering that the Russell are "made to measurement" I still get a better fit with the Arrow mocs - perhaps because they mold to the foot so well.
I also have a couple pairs of SoftStar "Runamocs" that have great ground feel with the 2 millimeter street soles. The sole is an extremely tough rubber composition made by Vibram and makes these shoes water proof on the bottom, at least. I use them as a minimalist running shoe. They look kind of funky, but are pretty useful and not too expensive. They totally let your feet splay out and be natural.
These flat-bottomed, no-heel shoes are all I wear any more and it has cured all the foot problems I have had in the past.