Eventide plugins have always used ilok and id certainly prefer a portable auth to carry around and use on any machine i like rather than have to deal with irritating challenge response type auths and be limited to 1 or 2 installations and not be portable.
I have over 150 auths for various plugins on my ilok it would take me hours to administrate if i had to deal with manual auth'ing them all.
Perhaps offering a choice would be a better solution.