I've been very pleased with the
Suspenz Smart AIRLESS DLX Cart
I have an L.L. Bean cart like
this one, except that the wheels are like those on the cart that Sardog1 has. It is fine for short distances, with an empty canoe, but the wheels and tires are pretty cheap and I'm not impressed with the quality of the tires. The rim broke on my first or second use. (Of course L.L. Bean gave replaced the cart.) Also, the wheels are pretty small diameter, which makes them less than ideal for rough terrain. So, I would
not recommend any of the carts with the wheels like what Sardog's & mine have. Unfortunately, most canoe & kayak carts have this type of cheap, small wheel.
Instead, I would recommend this type of cart:
Seattle Sports All Terrain Center Cart.
While I cannot attest to the build quality, it would appear to be solid, the wheels are much larger diameter & appear to be much better quality, & as a center cart, it will carry the weight much better than one designed to attach to the bow or stern. In the past L.L. Bean carried either this cart or one similar. It's not showing on their webpage now, but you might want to check to see if they'll have it next spring, or if it is available from one of their stores.