I'm assuming the x20 and the lunocet? In terms of where it matters, the x20 outperforms the lunocet by a long shot. I'm talking 50% better. Here's something that compares similar to the performance of the Lunocet (classic) at a faction of the price.
Yes I have those fins in the picture and yes they are similar in terms of effort required, number of undulations, speed and distance covered.
just eyeballing it, I think the lunocet has similar if not slightly less surface area than the x-20. By "slightly", I'm guessing about the size of your palm. I think the only unhappy customers about the Lunocet are the ones who value factors other than aesthetics.
The lack of performance is appalling after the big talk and reviews.
From the Lunocet (classic) site
It can take you great distances underwater with little exertion
The lunocet was born of a need for speed… underwater speed
The result?… The most efficient swim fin ever developed.
(all big talk with absolutely zero data to back all these claims up)
In hindsight, the few people who talk the Lunocet up are essentially people who have been bought over with free gear. They ignore negative comments, talk up irrelevant information that may seem to make the Lunocet really good and scoff at request for any performance data.
Delivery dates, post customer support, how he received feedback, lack of instructions, quality of materials, precision of manufacturing. performance.
Yes I could say I'm very unhappy with it.
I was once typing out a thread on why I wouldn't buy the Lunocet but I stopped halfway. Didn't like the negative energy I was feeling and I generally don't like to talk bad about people. I have since already taken a "I give up" approach despite being an active early contributor to the Lunocet thread.
I know of other customers (3) who are unhappy. They just can't be bothered to come to the forums and type about it.
Would you buy a brand new sexy looking car that required (amateur) fixing after you bought it? Then why would you buy a Lunocet?