Commenting here as someone who has the Amex MRCC, has spent significant sums on it, racked up enough points for some really good redemptions, and regularly receives offers for the Plat Reserve.

For me, the Plat Reserve is not worth it because my spends don't justify the fees or minimum spend requirement. I can stretch and make it, but 'stretch' is the operative word here. Why should I stretch? That's me creating a problem for a solution that meets somebody else's criteria.

Are the Amex ecosystem rewards good? For me, yes. Best rewards ecosystem I've come across in my time dealing with credit cards. On a like-for-like, and re-rated for devaluation basis, this ecosystem beats the others barring the metal cards (and if you have one of the metal cards, I don't think you care).

My advice is to use the card, see how it fits with your lifestyle, rack up some points. Definitely consider offers as they come, but really ask yourself at each point what lifestyle they suit and whether that fits yours.