I recently joined the Amex Starwood Preferred Guest Bzzcampaign through Bzzagent as well. Like many others, I definitely don't need any more credit cards, but was willing to learn about the card at least since none of the cards I have right now have any really great rewards to them. I also do not carry an Amex card.
The rewards look pretty good - you get pts you can use toward a stay at a Starwood hotel and bonus pts for signing up, room upgrades if you spend so much, etc. We like to travel so it sounds nice, unfortunately we have never stayed at a Starwood hotel and hadn't even heard of the brand before so I have decided not to apply for the card.