Read reviews for the Stern Wheels Cart by Quantum Engineering as submitted by your fellow paddlers. All of the reviews are created and written by paddlers like you, so be sure to submit your own review and be part of the community!
The downside is the hard wheels transmit every bump straight into my arm as I'm carrying the other end. This is especially fun on those concrete boat ramps that're made of concrete planks with gaps between the planks. It does plow in soft sand somewhat, but not as badly as I expected. Unless you have to go a long way in the sand or you have an especially heavy kayak, it should be good enough.
And the price was right, certainly by comparison to other products in this category.