I never like to generalize breeds into one lump category since there are sooo many different unique personalities among individuals ... but here I go anyway

I've never known Siamese to be bad around other cats at all. We get a lot of Siamese and Siamese mixes at the shelter and I am friends with the woman who runs the Siamese rescue here in my city, so I've seen tons of Siamese cats through the years. The only ones I've really seen who had aggressive attitudes were those that were declawed .. so they definately had their reasons!

Siamese are very vocal and can be independent, but I think I've met way more affectionate Siamese cats than independent ones.

I think you should go to the shelter and spend several hours visiting with the cat so you can make sure you like the personality. Any cat you bring home, Siamese or not, will require an adjustment period with your cat anyway. If you need help on how to introduce cats properly, just ask