The reader button works on 100% of amp links I've tested. If anything, the amp links help get me to reader mode faster by loading an optimized version of the page to begin with.
- Cnet: no
- Washington Post: yes
- Chicago Tribune: no x2
- Gizmodo: yes
- The Verge: yes
- Wired: yes
- LA Times: yes
- CNBC: no
- Time Money: no (broken)
Wouldn't call that working exactly.