You do want to stay at the hotel for a night before departure, correct? In that case, probably working with the SHS is good.
If you are just looking to park, then Park-n-Fly is $12/day for outdoor and $16/day indoor with a decent rewards program (for frequent parkers). Also, you can usually get free coupons on the internet for either 15-30% off or a free day.
The only time I used a Stay-Park-Fly Rate was when the hotel offered 14 days of parking following a stay and it was working out significantly cheaper than paying by the day at the long term parking lot. I didnt actually stay the night; just checked in, parked my car and left.