I've done one complete and am now practicing on a second of Metro's challenges in UC. While my computer's graphics card is too weak, and has been since Generations, I have no problem with playing in UC other than it's slow. But my game has been slow since Generations. Go figure! lol It's not any slower except around some of the big mansions. Pam's really slows the game down for some reason.
No brag but this town is the absolute best for challenges. Everything is so conveniently laid out that you save a tremendous amount of time getting from one place to another, and in a challenge this could be very important. Plus everything you need, except things from WA, is right close to hand. We could not place WA things because they would have been challenge breakers. There are enough cheap places to live so your new challenge Sim can actually afford a class or two and get started on the right foot. The furthest away place is the Science building but it is placed appropriately and I wouldn't change it at all. I'd like to see more fish in the pond in the park and at the lakes but there are plenty available in many, many other spots. Even some right outside my Thyme families back yard gate!
I loved Appaloosa because of all the animal things you can do, but UC is even better. It has the advantage of being beautiful everywhere you go, or comical if you count the run down area, and animals abound! We were a little concerned about animals spawning since this wasn't something we were particularly in control of, but it has all worked out just fine. Ana's starter farm is perfect for a beginning Horseman/woman and can turn into a truly awesome farm. It's my favorite starter home at the moment.
The more I play in UC and the more I try other towns I find UC is pretty much the only place I want to play. Phew!
