Once you purchase the Casa del Sol, you'll have a home that starts with a whopping population of 3,000 citizens, and can be upgraded by collecting from the building (or your friends can collect from them as well; all upgrades drop randomly) to a staggering figure of 5,500 citizens. If you're looking for a quick way (albeit expensive way) to unlock that next expansion by reaching your next population goal without adding multiple homes to your town, this would definitely be an easy way to get that done. However, at a price this high, even I'm not sure it's worth it.
Still, I suppose the building's rent potential could raise its value. You'll receive 156 coins every hour if you're prompt enough to routinely collect your earnings, which would give you upwards of 3,000 coins daily, if you were really on top of things. Still, does that justify the current cost of over $11 US for this single building? I'll leave you to be the judge of that.
What do you think of the Casa del Sol in CityVille? Will you purchase one of the expensive homes for your city, or would you rather purchase multiple, cheaper buildings instead? Let us know in the comments.