I've actually heard terrible things about the quality of their leather. I don't have any myself so I can't tell you first-hand.
I do love OnLead leashes though, and they are SUPER cheap and free shipping.
On Lead I have a euro leash from them and a regular 6ft leash
I've used my trainer's agitation harness (its actually called the tracking harness on their website).... he's had it 12yrs and only conditioned it once and its still in great shape to hold up to working dogs hitting it HARD. I've seen it used on Malinois, Dobes, an Aussie, and my GSD mixes. I know he uses their leads for his Malinois' too and they also seem to be in lovely shape. *shrug*
I had a training tab, but Scout ate it. It was good quality braided latigo leather. Nothing fancy, but it was good leather. Only thing I still have from them is a french linen tug, which is very nice btw.
That said my own harness is a leather walking harness from Stillwater Kennel Supply, it seems to fit the sled dog mutts chest's better than the traditionally designed agitation harnesses. And you just cannot beat Shane's quality and pricing honestly.
I had one of these:
All Weather Dog Harness with Quick Release, Schutzhund, Police K9, Tracking dog , Protection
But I sold it to a guy at training with an 18 month old Dobe because the design didn't fit Scout as well as my Stillwater harness. The hardware seemed too lightweight to me too, but I'm sure its fine I'm just used to bulldog grade equipment that is extremely heavy duty.
I also got a 10ft line of some kind of weather resistant stuff, I'm not sure if its biothane or what, but its a kick ass line. And a 4ft 1/2" OB lead out of the same stuff that is freaking awesome! And a couple more tugs that were on sale.