American Express has brought back a signup bonus of 35,000 Starpoints on the SPG Amex and the SPG Amex Business. The spending minimum is $3000 in 3 months for 25,000 Starpoints (the standard offer) and an additional $2000 in 6 months for a further 10,000 Starpoints. The offer ends 4/5/2017.
Those 35,000 points, plus the 5,000 you'll get for the spending required to earn them (for a total of 40,000), are good for 4 nights at the Walt Disney World Dolphin at its standard rate. I've seen specials where Dolphin rooms go for 8,000 per night, which means 40,000 points would be good for 5 nights.
Four nights at a resort on Disney property from a signup bonus is pretty good. Those 4 nights at the Dolphin would cost about $1000 through the Chase travel portal, which would require somewhere around 67,000 to 80,000 Chase Ultimate Reward points, for example. Or put another way, a typical Chase signup bonus of 50,000 UR points gets you $625 to $750 in hotel bookings, which will get you 3 or maybe 4 nights at a Disney value or moderate resort.
It's finally worth adding that if you combined this signup bonus with the Marriott's 80,000 point bonus, you would get an extra 27,666 points, good for another two nights at the Dolphin.