spg.com, starwood.com, sheraton.com, fourpoints.com, whotels.com, westin.com, luxurycollection.com, and stregis.com.

Will all these sites get you the same results of rooms available and price? Or does it vary; and is there an advantage to using westin.com, say, if booking a westin property, instead of spg.com? That is, do they all reference the same database?