There are some really great rates available with the United Fly Away sale, which still seems to be working. I was going to be at 23 nights, so booked two nights at a TownePlace at $51.35/nt to get up to 25 and make those last 15,000 points.

I do not believe that it's at all worth your while for $300, but if you could find a better rate it might be worth it. I plan on paying for the $51.35/nt rate with the proceeds from the 10% giftcard bonus promotion, so that makes it even better.