What wheel do you have now? Is it in good shape (i.e., drive band has good tension, footmen have good connection to conrod and treadle[s], all parts spin freely)?
Well-made wheels can work for over 150 years; ask many spinners who work on "old" wheels.
If at all possible, test the Louet; there's a direct-importer in Canada (but I don't know your location). It has lots of fans for its smooth action. I'm not familiar with the Cassandra, but why would a wooden wheel use PVC bobbins? The photo you linked doesn't show them.
Hope it all works out.