Texture can really make all the difference. I personally think the tentacle looks amazing, plus it glows in the dark!
Check out the reviews. The tentacle also has more 5 star reviews than the wave. Honestly I think it all comes down to what you want. I personally would go for the tentacle because it looks awesome, and the wave would be way too smooth for me.
Check out the wave product page
. The first video review there by Kayla shows the two side by side.