I bought the Lynx version second hand and agree with Akira, it's very impressive. Atari's little handheld was fantastic for the time. One thing this version has above the Amiga version - sprite scaling!
Still, one of the key things about Beast already mentioned by Galahad is the music, which really set the tone and atmosphere. Taking this into account, overall I still prefer the Amiga version to all others. Imagine if 512K expansions were common when it was released - the animation and other things may have been better.