Excellent

This product is simple, yet quite cleverly thought out, The bowls both hold a decent amount of food and water (although my cat still will not drink from them, and has never touched fresh water near her dry food bowls, She will still walk past 2 fresh water bowls for the dogs, and go outside for a drink from either a puddle, or the water feature that birds like to wash in, Go figure)
The bowls have a nice base that fits with an interference fit into the angled bowl holder, and as new no chance of the bowls tipping their contents onto the floor, only time will tell how long this last with the type of plastic used and the amount of times of removal and putting back etc. May need a shim in the future like some electrical tape to keep them having a nice snug fit.

I would say for our cat(not a very large cat) they would hold a good 4-5 days of dry food each, (YMMV) as she now has one bowl of whiskas, and the other used for dreamies cat treats, as she wont bother with the water, although as a lot of cat owners will probably say, if the bowl is not full to the brim, to a cat it is virtually empty and needs refilling NOW.

They are easy to clean, but i would be wary of bashing them into the washing up bowl with other utensils like cuttlery etc, as i think they will not take much to scratch the clear plastics, making them look tatty, and potentially a place for bacteria to multiply etc.
I can see the bowls needing replacing before the base perhaps, due to scratches, chips (maybe) etc.

I have knocked one star off, purely for the reason that there are no markings anywhere telling you the type of plastics they are made with, so recycling in the future may be a concern for some people. There were no markings on the box etc, which was not fancy at all, (no need, and helps reduce the price further)
And also the flashing on the underside at the top by the ears, is not as smooth as the rest of the bowl on the curved edge, not sharp, but not smooth either. But a definite lip to them.