I think the wire ones are more feline friendly. They can see where they're going, and don't have to be shoved into an enclosed tunnel.
I bought mine from my vets years ago. It's a large one, intended for two cats or a small dog. Funnily, Sam and Polly haven't used it together. Instead, they have lots of room on their own. Also, if they have an 'accident' in the taxi, they can sit away from the poo. (The drivers hate it; serve them right for driving over the bumps!)