On the subject of migrating, please check the Import System forum at www.vbulletin.com/forum. You will find a topic on the top with a list of all supported migrations. If yours is not mentioned or you still have questions on that, please post in the Pre-Sales forum at vbulletin.com.
The look and feel of vBulletin can easily be adjusted to your own needs by modifying templates. For most changes you will only need some HTML knowledge, or you can hire someone who can do it for you.
About specific functions that might not be supported by the default vBulletin installation, we have a very active community here at vBulletin.org that release a lot of modification to the standard coding.
Feel free to look around here on the forums, and if you have specific questions, to ask them in here.
Looking forward to see you running a vBulletin board soon.