Wish I had a couple to compare.
The infos say that the Spirit is the same Voodoo design and durability, except with less expensive heavier materials.
So the Spirit is supposed to be the econo version of the Voodoo to help entry level flyers.
Besides KiteForum.com, and the Flysurfer sites (including Flysurfer-USA), http://www.foils.nl
are excellent places to find more details.
LEIs are awesome, I prefere my 15.5 in 14-22kts in the surf,
AND on the FOILs side, I have to give great respect to Flysurfer quality.
I still fly a 2001 Mastair 16 in 8-14kts (on the water, not land) and I'm amazed at the aviation standard durabilty, built like a paraglider wing.
The MA16 has atleast a couple good seasons left, but I could sure use a Titan 18.5 or 22.5 for the coming summer NW Florida light wind duldrums.