Preference for speakers that are half the price. Has this ever happened to you?

Its a bonus if your preference costs less. In this case there are likely particular reasons for your preference. Both the Aida 2 and IC Ex3me are in the Sonus Faber reference line so each benefits from SF's best engineering, parts quality, etc. The Aida 2 is a great representation of the Sonus Faber house sound-very smooth and pleasing but a bit colored and sacrificing some detail to achieve its sound. In contrast, the Ex3me is a "concept" speaker that is a significant departure from anything else Sonus Faber builds. It features a beryllium tweeter and is tuned to be very transparent and detailed, less colored than other SF speakers which may sound more natural to you. So, the comparison was between the the typical SF house sound vs. something very different. It would be interesting if you compared the "regular" version of the Il Cremonese to the Aida-you might well prefer the Aida.

I had a similar experience. After years of enjoying the Vanersteen 1ci, I thought moving up to the Treo CT would provide greater enjoyment. But for me, it just was not the case. To my ears, the 1's just have more meat on the bone, greater slam, more bass output, and are just more fun to listen to. Perhaps the Treo's are just too "refined" for my tastes. Sold the Treos and still have the 1's. YMMV

The 1Ci is a ridiculously good value when setup correctly and well driven. 

Lol 40 years ago l spent the afternoon auditioning speakers at a hi end shop. One at a time the owner brought out various brands and models and after a few hours l had a splitting headache and decided to call it a day. I really didn’t like any of them. On the way out by the door l noticed a couple of JPW Sonata bookshelves and asked him to set them up. It took me literally a minute to say “I’ll take ‘em”. They sounded natural with good detail and I knew they would work for me. And when I got the price which was significantly less expensive than anything else I had heard, it was a no brainer. 

l ended up enjoying them for the next 35 years. Get what you like and don’t worry about it!

In this industry, price barely matters one you get north of $1,500. After that, it's pretty much subjective preference. The fact that you think more expensive speakers should sound better is exactly why this hobby is dying. Buy what you like, not what marketing snake oil primes you to like. 

I've heard speakers that cost 4 times what mine cost and I prefer mine.  I haven't heard them in my system, but they were driven by nice electronics.  The owner loves his speakers and that's what matters.