Great posts ladies!!
I'll add a few thoughts .. specific to my two Cake Monsters:
They are an absolute riot together, and .. like many people have read/heard .. play more like puppies than birds. They're not picky eaters, and pretty much eat everything offered. I often call them my "feathered goats" .. they'll eat just about anything. They don't really have any phobias .. no fear of new toys or objects, and will play with a variety of different shapes, textures and materials. They LOVE baskets filled with footie toys to roll around in.
My two LOVE to bathe .. in a water bowl, they don't much care for a spray bottle, but oddly enough, will tolerate a misting from the shower or, in summer months, outside with the hose.
As other's have stated, they are super charged birds, extremely high energy. They love to play and can turn just about anything into a toy or gym. A top to a pop bottle or milk carton could keep them occupied .. well for a few solid minutes .. they do have a bit of A.D.D.
As far as the Bad/Ugly .. well, there's been a lot of that here as well. I'm hesitant to really lay it out, because I don't want to "scare" people away from Caiques, but .. I do want people to know what they "could" be in for.
I mentioned having "A.D.D." .. it's fun having birds who like to play with different things, but .. because they seem to lack focus <mine do anyway>, nothing will really keep their interest for very long, and then they want to move on to something else. They won't play with a footie for longer than a minute or two before becoming bored and wanting a different toy, for instance.
They can be loud, and since I have big Macs, loudness to me is relative. They have a very annoying "Piggy Squeal" thing they do, and boy oh boy, it can make my ears and eyes bleed. Ever see the Geico commercials with the pig yelling "Wheeeeeeeeeeeeee" .. well, that .. times 100 .. for long periods of time. While they don't have the volume of my big Macs .. their pitch is a lot higher. I can often hear them above all the others in my home just because of the pitch/tone of their screams.
They can, and usually are, bird aggressive. My two would absolutely do harm to/kill a bird of similar size, and they have no fear around the bigger guys either. They mean business, they're not bluffing or testing. They can and will do serious harm, this is no joke. I knew Caiques often didn't get along with other species of birds, which is why I got two at the same time <mine are siblings>. Their style of play is also a factor, they don't play like birds, they play like puppies and most birds don't appreciate that style of play.
Even having two Caiques is no guarantee of harmony. They've been known to turn on their cage mate .. and I've read several stories about one Cake killing it's long time cage mate. So, you must be ever vigilant about their behavior towards each other as well as with other birds.
They're not hard birds to read by any means, however, their change from "good" to "evil" can be so fast that you never see it coming .. in a blink .. your Cake is ripping you apart, when just a moment ago, he was a cuddle bug. It's like Dr. Jekyll/Mr. Hyde .. or a severe case of unmedicated Bi-Polar disorder .. a switch in their brains just flips and they lose it big time.
They can really be nasty during hormonal periods. It seems most Caiques are given up from the ages of 3 yrs. to 7 yrs. old. I gather this is when they're at their worst. I've had some really difficult battles with my two, and they'll be 5 yrs. old come this October. They really went off the rails just before their 4th birthdays. It was no fun at all.
They will stalk you, chase you down a hallway, jump/fly from whatever they're on to do damage if you're the one who is currently on their poop list. They mean business too. Their bites are NASTY!! I've got birds 10 times their size I'd rather take a bite from. They use the sides of their beaks to really grind in .. resulting in a bite that is not just deep, but usually removes a ton of skin.
They with throw themselves at their cages bars so violently that you think they'd hurt themselves if they want to get you.
I know I don't paint a pretty picture of Caiques, and I know quite a few people have absolutely sweet Caiques <Saroj .. with JoJo and Chickie .. whom I'm so jealous of!!>. However, a lot of the information out there on Caiques doesn't really give the truly ugly side of their personalities. You always hear about "clowns of the parrot world, playful, high energy" .. but there is a much darker side to this species.
It takes a certain personality to deal with them I think, they are DEFINITELY not for everyone. I certainly would NOT recommend a Cake to anyone who needs a "everyone must get along" dynamic in their household. I would NOT recommend them for people with young children .. Cakes have thing for faces/facial bites .. not good for an adult, but absolutely horrible if it's a child.
Anyway, that's my view of Caiques. They can be absolutely awesome birds, and not all of them will be like my two. Just be aware of what the potential future could be before getting a Caique.