Mm, chinchillas .. tasty little things.
Anyway, I owned a chinchilla for a few months and thought I'd share my own experiences;
Cons (bad news first):
1. They shit a -lot-. I am still finding shit behind beds, couches, et cetera. So, yes, you can have them run around, but be prepared to pay the price. On the other hand, they're hard, dry little pellets.
2. Their scream. It sounds like someone mauling a squeaky-toy while strangling a cat, through an airhorn. They scream at the smell of blood, too. So for you other chicks, move the cage out of your room every month or so ;).
3. Nocturnal. They will nap all day and refuse to interact with you, so they can run around their cage and squeal at night. Another good reason to not keep the cage in the same room you sleep in.
4. Shedding. If the bugger doesn't completely trust you, it will shed massive clumps of that soft, fluffy fur when you attempt to pick it up. Or whenever it feels like it.
5. St-u-u-u-u-pid. They will run into things and hurt themselves, trust me. About three weeks into owning the critter (before I learned it was a -really- bad idea to let it run amok in the house), it charged full-blast into something? on my floor and I ended up with a one-eyed chinchilla. Just think about the joys of giving a frightened rodent eyedrops and medicine three times a day, for six weeks.
6. Chewing. They need hay, and blocks of wood to chew on. If you let them out of their cage, no matter HOW much you think you have them trained, they will chew you furniture, and they love the taste of books.
7. Escape artists. See all of the above for why this could be a problem.
8. Long life. Will you still want this monster a few years down the road? Unlike rats or mice, chinchillas can easily live 5 years.
1. Relatively easy maintenance. You feed them hay (yes, alfalfa hay) and pellets.
2. Practically no smell, from the feces and urine.
3. Fairly inexpensive to keep, despite initial high costs.
4. They don't get fleas or ticks. No joke; their fur is too fine and densely packed. So when the bubonic plague returns, we can trust the chinchillas.
5. Cute .. fuzzy. They can be quite affectionate after they get to know you.
Other notes: Don't use cat litter with those 'smell good' crystals - the chinchillas will eat the crystals. Not good.
The dust-gray chinchillas are the 'standard' types, and by far the cheapest. The exotic colors can run easily into hundreds and hundreds of dollars.
My chinchilla was a gray male, dubbed Dante. I bought him for $40 from a family moving away, and ended up selling him to the caretaker of a day-care center several months later, when my family insisted I get rid of him.
I hope anyone thinking about purchasing one will consider these points before getting one ;). Dante was an interesting experience, after raising sheep, cats, parakeets, rats, ducks, chickens, emus, llamas, and all the other animals I can't remember offhand.