hori hori gardening knives?

My brother in law is turning 40 and is really into gardening, so we're thinking of getting him a nice Japanese Hori Hori gardening knives. Unfortunately, we don't really know much about them, so I'm hoping someone here has some input on the subject.

What are some good hori hori knives and where should I buy one (within Canada is preferred, just to avoid long delays, but not absolutely necessary)? What makes a hori hori knife good?

There's at least 10 people chipping in, so we have a pretty sizeable budget.

Thanks!