I actually found the companion coupon to be disappointing. It's not a true B1G1 offer, since you can't use it on Amtrak's lowest fare bucket.
So if you calculate the fee card's value based on what you think you're going to save using the companion coupon, you have to take into account that your free companion ticket is not actually free (assuming you would otherwise be booking low bucket).
Good point, fairviewroad. When a saver fare is 20% below the lowest coupon-eligible (value) fare, then the companion coupon is effectively a "buy 1, get 75% off a companion" compared to two saver fares.
On the other hand, I'm 2 for 2 on applying upgrades to NER saver fares. If upgrades on saver fares work systemwide, then that's good "value" by me.
I value the companion and upgrade coupons at a totally subjective $30 each. Add TQPs and category bonuses, and the annual fee remains worthwhile to me.