Bohnanza Fan Edition
I think the biggest issue with the fan cards is that they don't contain the quantity of that type of bean in the deck.  If you're prepared to mark the face of the cards, then adding "12" to all your Soy Beans would improve the playability greatly.

The second thing that's missing from the fan cards is the bean name.  Having the numbers alone would be fine to identify which beans are from the same set (as well as the icons in the top corners), but the negotiation is helped along by everyone using the same names.  If you have room on the cards you could try adding this information too, but I would prefer to print off a few crib sheets to have in the centre of the table, showing the bean icon, the quantity and the name.

On a side note, I love the gameplay in Bohnanza, but quite dislike the artwork.  I think the fan edition may prove to be a good investment once you've got used to it!