Thanks travelswithmyself and tillephone for your responses.

Yes, I definitely want to stay at the Westin Cancun Resort and not the Westin Lagunamar. One reason is that I want to get night credits and my Platinum perks, which I wouldn't if I rented a timeshare from a 3rd party. The second is quite frankly, price. It's just the two of us, so the Royal Beach Club rooms will serve our purpose nicely and we don't need all the space that the Lagunamar rooms offer.

I did see the Sunsational savings but my corporate rate can do better. Since I first posted this, I looked through the Promos thread and there is a 25% off 6 night stay that gives good savings ... but it is a non-cancellable rate. Given how September is still pretty far into the future, I don't dare book a non-cancellable rate ... my schedule still has a high potential for changes .

I think what I might do is book using my corporate rate and continue to check periodically as we get closer. If you have any other ideas, I'd appreciate hearing them.