Are dome midrange better than cone designs?

I was really enthused until I read Jtgofish's problems with imaging.
It is pretty simple to put the 4" Flexbar into a pre-made .375 cu-ft Parts-Express cabinet. Mating a good tweeter may be the problem as Audio technology recommends an x-over of 6kHz. X-over that low means it needs to be done right. i would imagine with such a high quality mid any defect will be VERY noticeable.
Just looking at parts cost, this speaker would be ~$800. use typical hi-fi 6x mark-up and they would cost $4,800 in a salon. Pretty good value if they can be done right.
I am afraid they will be too good and I'll have to upgrade to $10,000 Atma-shpere amps.

Thanks Shadorne for the link.

I really like the ATC's I have heard. One problem for me is the need to be played loud before they come alive. Shadorne's ATC link also mentioned this.
Is this true with all dome mid's? I only listen at 60-70dB and 75 is getting pretty loud. That is why I have been able to live with tang-bands 3' ~full range speaker.