I received an athena envy yesterday as I needed a side-by-side for my bigger/more power requiring atty's (ordered it before I knew about the Ysticks which made it to my basket somehow).
I must say it is a pretty nice mod, it fits the mutanks perfectly, like it's made for it (just the top fill section sticks out, just what you want), only drawback: it's pretty wide.
I think I do prefer it over the clown sticks, because of the bugs in those, but no way it beats the authentic Xvostick, that one is so much nicer in the hand, it is still my most used mod.
Thought about selling the Athena straight away, as I have the Ystick on order, but I think I'll keep it because off the deeper well.
When choosing between the clownstick and the Athena I think the deciding factor is what atty's you want to use, the clownstick fits smaller atty's perfectly (kabuki, GM with heatsink) and the Athena fits bigger ones (> 62mm).
Some size comparing pics: