V-Weaves for my Medium, Channel Weaves for my Very-Maxi collie.
I've found for smaller dogs, V-weaves are better for footwork and the poles are more obvious (in wide open Channel weaves, they don't really clock the poles as being part of the same obstacle). Have to admit I also found weave entries a lot easier to teach in V-Weaves. For larger dogs, I've found that Channel Weaves tend to work better for footwork and also that with Dylan in the V's, he tripped over the poles a lot and started jumping, which he never did in the Channels.
Think it's a matter of trying different things for different dogs though, I know a friend of mine taught her youngest by luring through uprights with a ball-launcher and he has brilliant fast independent weaves. I don't think I have the co-ordination for that method, I'd probably end up knocking my dog out with the ball launcher and getting tangled in the weaves myself!
