Rip them apart, eh? Heh. Well, i'll try. Though others around here can probably do a better job.
#1 - Looks more like "Exen" Color might help set the T out. Nice and compact, though i can't figure out why some things are there, like the little "tooth" on the T. This is probably my least favorite in B/W, but i can imagine potential in color.
#2 - My wife preferred this one (i always like her feedback on aesthetic decisions), though she would prefer a more internally consistent font. She also didn't think the 'n' on the end should connect to the underline. As for myself, i don't like the way the T sticks out so far to the left. I personally like the e's and the x. Color again, could add a lot.
#3 - I think this is my favorite at this point, though i struggle to articulate why. I'm also least sure how to rip this one apart.
Anyone else got feedback on this? If so, sooner is better, as this is a GHOP contest issue and there is a time limit for the task (only loosely enforced, of course .