IMO this deal is not good. I used the rewards app and have gotten lots of reward stars through promotion and normal use. I think you need $4 dollars for each star on the credit card. The silver lining is you can use the card anywhere to spend $500.
I've received a 6500 bonus star offer several times now with the $500 spend. It's not a bad offer as 6500 stars equals to 52 free drinks/items. That itself isn't bad but the card has an annual fee - $49 per year. if you take the 52 drinks and times that by $5, that's $260. It's not a bad card but with an AF, I don't think it's worth it. If it had no AF, then it definitely would be worth it but compared to another card, say BoA Cash Rewards (no AF, $200 on 500 spend), it works out to be a better value. Hence why not many people are getting it (unless you love Starbucks and drink it daily). Just my 2 cents.