This Sonic Adventure Chao is one of the more sought-after plushes. It's large size (10 inches) and quality really put it over the top. As you can see, they've used big plastic for the eyes, and the wings are 3D and textured. The soft yellow on the tips makes it look just like in the game!
Whenever this comes up on Ebay, it's usually really pricy, but it's so cute, it's worth it to collect! 

Here's a good look at the turn-arounds for the large, expensive Sonic Adventure 1 chao plush. The set just had a neutral chao, but it was really well made (like everything else on the set) With these photos you can see they used a nice fade for the yellow on the feet & head tip. The pink wings are nice & big. Do note the cloth tag, to help avoid fakes. It says 1999, which makes sense with the release of Sonic Adventure 1.