For those that say they are overpriced I would be interested in which less expensive speakers sounded better to you.
It goes without saying in this hobby that 'better ' is pretty arbitrary and about personal preference, especially for speakers.
That being said, when explicitly looking at US MSRP, to me the outlier in the Harbeth line is the cost of the 40.3XD.
e.g.
https://store.acousticsounds.com/d/132377/Spendor-SPENDOR_CLASSIC_100-Speakers
vs
https://store.acousticsounds.com/d/154678/Harbeth_Speakers-Monitor_403_XD-Speakers
I've seen some used 40.3s recently going for prices I would feel comfortable paying for them if I thought I could make them work in my smallish room.
It is not like there are no other high quality speakers that MSRP around its used prices though. Here is my current upgrade list and I've been able to demo 3 of them so far with more to come shortly hopefully.
I'm not going to argue any or all of these are 'better' than the $24.5K 40.3, but I think it is safe to say the 40.3 has some serious competition at its current price point in the US...
Vandy Quatro Wood CT $18K
Vivid Kaya 45 $18K
Joseph Audio Perspective2 $15K
Yamaha NS5000 $15K
Spendor D9.2 $13K (currently own D9s when MSRP was $10K and 40.2 $15K).
Fleetwood Deville $12.6K
Fyne F1-8 and 7 series $10 to $14K