panels vs cones which is best and why ?

I'm glad you like panels - good choice. Did you have a specific question, or observation, or are you looking for validation of some sort?

my observation about cone speakers is that for many cone designs the audible flaws make ownership for an extended period of time a challenge.

i personally have a problem with the upper mids and lower treble response from a dome tweeter.

in all i think it is harder to design a "good" cone than a "good" panel, and yet cones are more popular--go figure.

My Quads and Acoustats are in the closet. I have no problems such as you have described with the box speakers that succeeded them, but then I choose my amplification very carefully to match my speakers needs. Go figure.