I've tried to pick up cake on several occasions to "fill the gap" on some project. In the end, I've never gotten it to fit, there is a large gap in examples.. Excluding Hello World, and Your first blog. Cake assumes you'll automagically know the proper/best/their way of doing things, and when you don't you can't really find examples of how to do things the "right way".
The html handling is also pretty basic, I had a need for multiple skins for a site based on different environmental factors, and I found myself struggling more with the skin handling than writing for the business logic of the site. Default cake installs it's own cake templates if you don't have anything there, but this makes it hard to figure out what you have to put out there.
I'm also concerned that I've not seen any "big" apps deployed in Cake. Rails has tons of examples like most of the stuff from the folks that did BasecampHQ. I've just not seen Cake really picked up in general.
One of the best parts about Cake can also be a big old pain in the ****. Cake itself is kept ENTIRELY separate from your code, I think this is AWESOME. Upgrading cake distrobutions becomes so much simpler, since you don't have to worry about hacks, and other issues it all just upgrades nicely. I did download a previous cake version, wrote a couple quick apps then upgraded it with no problem. Of course there may be times where your code might conflict, but the chances are also so much less than other frameworks.
This separation is also a major pain in the neck until you get to understand it. For the longest time I threw my hands up in the air and left it in the "development" state because everytime I tried to break out the directories, it blew up on me. I hate fighting with a framework! In the end I finally understood it, and the crazy pathfinding capabilities, but it's a pain unless you get it, and getting it can be tough.
In all, I've not seen a project through to completion with Cake, I'm certain it's because I find I can get things done faster doing it "my way", no matter how much I would like to use this type of framework.
I'd like to see some applications come out using Cake that are groundbreakers, I think the developers have a good thing, if the rest of us can wrap thier heads around it.