I've been looking at this question a lot lately and I've come the conclusion that the Green Card is a waste of time for almost everyone. Simply, there are better cards out there now; the Green Card exists almost just as a relic to the past. From Amex's own lineup you have the PRG, the Starwood Card, and arguably the Zync Card that are better. Not to mention cards from other lenders, like the Chase Sapphire Preferred, which packs a lot more punch for the same annual fee as the Green.
The Zync card is by far a better choice for the low to moderate spender because they won't accumulate MR points fast enough to overcome the Green's AF. Not only that, but the Zync can earn MRE points faster with packs and still be cheaper. Even if a low spender wants to transfer points, he can use the Zync (or Blue) to rack up MRE points for several years then get a Green just before he wants to transfer points and close the Green before the annual fee hits.
If you are a moderate to high spender that would spend enough to benefit enough from the Green to keep it open all the time, you would almost certainly benefit more from the Premier Rewards Gold or the Starwood Card. The PRG bonus for $30K spend and the multipliers should easily make the PR Gold a better choice than the Green. Also the Starwood Card has a lower annual fee than Green and earns points that are more useful. Starwood has more transfer airline partners and the points can also can be quite valuable when just used at their hotels.
Plus you have the Chase Sapphire Preferred, which is just a flat out better card than the Green: no forex, dedicated US customer service, bonus point categories, concierge, no acceptance issues. If you are thinking about the side benefits like extended warranty, purchase protection, return protection, they are roughly on par with Amex. It also has price protection, which Amex lacks. Chase's UR also has some nice transfer partners, arguably better ones. You can also add a Freedom to the mix and earn 5x points in rotating categories. All the bonus points can make the CSP even a good deal for moderate spenders who couldn't get enough value from the Green or PRG.
The Green just doesn't make much sense anymore, save for those who've accumulated a lot of MRE points with Zync already or perhaps those who've had the PRG or Platinum and want to keep their MR points. I'm not sure what I'll be doing with mine when the next annual fee hits. I'm moving most of my spending to the Sapphire Preferred and Freedom. I think I might transfer out my points, especially if a nice bonus appears, and keep the card as a Zync for another year.
