I've only ridden the Crazyfly. I really liked it and have seriously considered getting it, but I've been wanting to demo some others before I commit. The Nobile looks very similar in shape, but it has a flat tail which may give it slightly better pop for tricks. I do like that the Crazyfly is 135cm vs the Nobile at 130cm, but that's just a personal preference because I have long legs and a wider stance.
I'm not familiar with Circle1, but based on their website, the carbon model has the best shape imo.
Have you checked out Liquid Force's 2015 Kite Skim?
http://liquidforcekites.com/product/boards/kite-skim/
Slingshot's 2015 Skim Bender is also perfect for kiting (fin option), but they market it under their wakesurfer category.
http://www.slingshotsports.com/2015-Ski ... WjP7Shy_Hg
LF also has three other skimboards perfect for kiting (fin option) that they market under their wakesurfer category. I've been eyeballing the Doum Pro 54 because it can be set it up as a thruster, a twin, single fin, or no fins depending on the conditions just like Slingshot's.
http://www.liquidforce.com/wakesurfers.html
There are some older Slingshot, LF, and Airush kite skimboards still floating around online too.
Beachdog Skim is another one to check, but I'm not sure if they're still available.
http://beachdogskim.com/