I have got it down to 2 speakers to pick from.

Dali Epicon 8 or Duntech Senator. Yes I have heard both.

I have a Diablo 250 to drive either of them.

What would you go for?

Both seem to retail for ~$30k but A2A has the Dali for $11k

Not sure what to read into that

My feeling, without having heard either, is that the Duntech should be a much better speaker but it's quite a big price difference now!

Which did you prefer?

Well I write here what I think is true.

Dali speakers are generally designed to be pointed straight ahead and not directly at the listener.
Their on axis frequency response is not flat as they have louder than flat high frequencies and will seemingly sound bright when pointed at the listener.
This is attenuated by as mentioned pointing them straight into the room and not at the listener, so probably about 30 degrees off axis to the sweet spot, and then their frequency response is much more flat in the high frequencies and so less "bright" sounding.

Those Scan-Speak Revelato tweeters on the Duntech have a reputation to beam at high frequencies and I think this is shown here.
If, so they seem to favour being pointed at the listener (red line?) or a bit off access, perhaps about 10 degrees (green line?).
https://www.soundstageaustralia.com/index.php/reviews/639-duntech-audio-senator-loudspeakers

Edited 20 hours ago20 hr by Satanica