It's actually faster now that the Clarion is closed.
The shuttle bus used to wait at the Clarion hotel lobby, then it took an extra 10 mins to get through that lot and stop at the gate between the hotels.
As long as you don't mind walking to the Westin, this lot is good.
(Although it seems the shuttles for pickup at the airport don't run as often as the other parking shuttles. I believe they only have 2 of them)