Plus the AP allows you to get the DDE.
It's like disneynutz said, it really depends on your travel plans. Having been to Disney so many times through the years, I no longer visit a park every day when I am there. A ten day hopper will get me through a few trips (usually 3), and those trips may be spaced out over 15 - 18 months. I did the AP's a few years, but as time goes on, the 10-day non-expiring fits my needs better.
Is the 20% good at every place or just a few select restaurants? I never heard of this card before and we have a ADR so we should be eligible, or do you have to buy it when you get your ADR?