Compared to Légère reeds N. 4 and N. 3.25, Ambpoly classic is surprisingly responsive, especially in the altissimi notes with Selmer Concept mouthpiece. I'm also happy to find out that its performance on intonation is also very consistent and relatively easier to control. If you've used Vandoren or Légère reeds, you'll probably hard to believe it's a N. 3.75 reed.
The sound, however, is quite a different taste compared to the Légère reeds. It's sharper, delicate and less powerful, more in higher frequencies and less in lower frequencies, I would also say Légère reeds have a broader and warmer sound. Mount the Ambipoly reed a bit outer than the mouthpiece tip to get a thicker sound, don't worry it'll still be very responsive. I suspect the it's because the facing of Ambiply is completely polished while that of Légère is a bit textured, thus creates the difference.
If you want to give plastic reeds a try, I'd recommend you try this out.