Welcome aboard.
It is my opinion that you MIGHT want to keep what you have. And here's why:
As Westin finishes the north property and begins construction on the new development to the far north in Maui, and as Westin continues to expand to other great locations, I believe that getting into Maui will be much easier, both for SVN owners and for II owners who wish to trade into Maui. Since you are an owner there, I assume that you'd get priority anyway when it comes to upgrades vs. others who simply traded in. (And I say this based on nothing but what seems fair to me.) So you might be paying an extra $12.5 for something they would have given you for free. (And the fact that they low-balled the figure makes me even more suspicious.)
Unfortunately they don't publish their pecking order for upgrades, so I can't guarantee this, but it seems reasonable that their pecking order is: SVN resort owners, SVN traders, II owners, rentals. But they might decide not to upgrade home resort folks at all in order to entice them to upgrade their view. Who knows?
(Someone here suggested another idea which I think is pretty crafty. IV owners should not use their home resort booking period at all but instead should call at the 9 month mark and be treated as any other SVN owner trading in. Since SVN owners in will definitely get priority over II owners trading in, even if SVN decides not to upgrade home resort owners you'd hopscotch over other IV owners by waiting for the SVN Priority window and being at the top of that list. Of course, this idea might not work during a very popular week.)
Another reason that you may want to keep what you already have is if you plan to do a lot of trading, either via SVN or II. As an OF owner, I am very reluctant to do SVN or II trades because you don't carry your view with you. Once I travel to another resort, my premium OF view goes out the proverbial window and I'm in queue along with everyone else, including IV/OV owners. So IV owners definitely get a better deal overall when it comes to trading to other resorts because you are given the same number of StarOptions as OV/OF owners, at a fraction of the price! The trading power of 148,100 StarOptions for the price you paid, $22.5k, seems like a dream deal.
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That being said, acc. to FredM, OV resales are currently going for $49.5 and developer price is listed at $65.9k. So $34.5 all in beats even the current resale price. If you're going to be spending a lot of time at your home resort, and if view is important to you and you don't want to stress about being upgraded, you might want to go ahead and take the offer now. Of course, for all the reasons I mentioned, I'd certainly ask for a boatload of StarPoints while I was at it. (Hey, it doesn't hurt to ask.)
Good luck with your decision.
