I quite agree: comparing intelligence across species is not usually directly possible. Cats simply think differently to dogs.

ObCat anecdote: I live with an aging tabby who is usually fairly cluey. She gets put under the house at night and our house has a configuration where the other side of some internal walls is under the house. There is also a cat-flap on the side allowing cat-access from outside to under. When Dad first cut the hole allowing access from inside to under, it took this cat less than 10 minutes to figure out the two flaps led to the same place! I'm sure our other cat still re-discovers this every other day or so...

Wade.