I just went through the same analysis. Here are some things to consider:
* Same UY, banking window.
* Points can be pooled (regardless of resort) at the 7 month mark with the same UY. This only comes into play if you need enough points to make a reservation and neither contract has enough to cover the night. For example, if I need 30 points to cover a night and my SSR's contract has 15 points and my VB contract has same UY, I can pool the points and make the ressie. If different, I have to transfer 15 points from one contract to the other. You are only allowed 1 transfer (in or out) per year. (Note: if you add on through resale with the same UY, make sure you specify in the contract that you want the points added on to your existing master contract).
* If you travel at different times of the year, having separate UYs can actually be of benefit. For example, if you take regular trips in May and November, having enough points to cover your May trips with a April UY and a separate contract to cover your November trips with an Oct UY will give you the most flexibility with banking, rescheduling, borrowing, etc.
Overall, I didn't think the "cons" were all that great and just made an offer on a contract with a different UY. Sure, it would be nice to be able to pool the points to make a reservation. However, the benefits of having a different UY far outweighed watching a separate banking window and having to deal with a transfer on occasion.
This is all based on what I've read. Others with actual experience may have more valuable advice!!!
