Kamran, If I was starting today trying open back designs for the first time, I would take a simpler approach.
My pleasure has come about over a long time and began well before many had even tried to hear the differences using speakers without a box.
My eye opening phases came in my youth from fixing old radios with my dad, many of which had large speakers in an open back semi-enclosure.
I have not heard the Lii 15s, but I have heard enough from some folks I respect and trust to not steer me wrong, to make me just get some and live with them for a bit. Just to see for myself.
That is the only way I can assess things like speakers. I have to have them in my own hands and hear them my way.
I can not recommend the Lii drivers personally, because I have not heard them, but my curiousity is so high, that when I can, I plan to own a pair and see for myself.
That is how and why I bought my first Decware product. I finally just said, OK, what's all this noise about? ... and bought one.
Now, it's impossible to go back. So I got another and another.
If you can find a way to hear some of the gear you want to try, do so. If not, that Leap Of Faith thing comes into play or as the old horrible saying goes, "suck it and see" ... or consider that the entire process is like going on a date. How much have we all spent on dates?
You don't have to pay alimony if you decide a speaker does not do what you want.
The best part of that quip is that you are the Judge!