I got on it on Humble Bundle too, and I do this Game Jam mostly to try these new softwares. I think the palette is easier to use, it's a faster way to draw : you have only one image on your canvas, you can add some glow easily ... I didn't try animation for now, but I guess with only one tile, it could be harder.
I used PyxelEdit before (still using it on my other project), and I think I will use Hexels when I want to do animation with Spriter (like in Inspector Waffles).
I forgot to mention that you can draw with a lot of different styles in Hexels : not only pixel but hexel, trixel, mosaic styles ... For an isometric games, with trixels, it will be so great to do it with this soft.
And I'm not working for them, just telling my opinion ;)