For same values of "cheaper" and "better". The Mavic is better if you want something 200g lighter with fully replaceable bearings. The Shimano is better if you want easily replaceable spokes and simple to service bearings, with the penalty that a worn out bearing means the whole wheel is toast. The Shimano is cheaper in absolute terms, but the Mavic is cheaper relative to its new price. I'd expect the Mavic to sell at CA$125, and I'd expect you to outbid any other interested parties if you offered CA$50 for the Shimano.
For same values of "cheaper" and "better". The Mavic is better if you want something 200g lighter with fully replaceable bearings. The Shimano is better if you want easily replaceable spokes and simple to service bearings, with the penalty that a worn out bearing means the whole wheel is toast. The Shimano is cheaper in absolute terms, but the Mavic is cheaper relative to its new price. I'd expect the Mavic to sell at CA$125, and I'd expect you to outbid any other interested parties if you offered CA$50 for the Shimano.