Auditioned Wilson Sabrina X vs B&W 803D4 and Shocked

Not at all surprised by your findings. We don’t all share the same size/shape/age ears. Nor do we all share the same language and dialect (which does affect how we perceive sounds). So it shouldn’t come as a huge surprise that we don’t share the same preferences. The Toole school would like us to believe that’s the case but it’s not—probably the reason for why B&W doesn’t bother to make flat measuring speakers any longer.

B&W’s 800 series employs one of the best tweeters in existence, which goes a long way in mitigating listener fatigue despite the tipped up response.

@OP - If that is how the Sabrina Xs sounded, they were not set up properly.

I have not heard the B&W's, although I had 805's at one point.  However, the Sabrina X's in my system definitely do not sound as you describe it.  I have a Pass 250.8 and an ARC REF 6 pre to drive them, and to my ears, the combination is the perfect mix of width and depth of soundstage, black background and great placement of instruments. The Wilsons just do it right in my system and small music room.   I think that that treble is smooth -- perhaps too smooth when coupled with the McIntosh gear.  Just goes to show that everything makes a difference, and it is really difficult to compare the sound of one system with an entirely different system.

As a few others have said, McIntosh and Wilson are not a great match. I have heard this combo for a couple of decades with different Wilsons and different McIntosh products. 

For my tastes, and I will state here, that I am not a Wilson fanboy, Wilson with a better matching amp, will sound better, than McIntosh with the B&W.

@simonmoon In my experience and via my dealer etc, Wilson and D’Agostino are two very good matches for Wilson. I have the Sabrina X with a MA8950. I was split between the 803 D4 and the Sabrina X. I strongly went in planning to go 803 but the Sabrina X blew it out of the water. The McIntosh has a lot of power which is what the Wilson’s want. Wilson will often demo their speakers using McIntosh Amps. Cables matters as well. Wilson uses Transparent Cable internally and often for demo's. 

Based on how highly the Sabrina X is reviewed, I would make sure the setup at your dealer was ideal. The Sabrina definitely goes lower than the 803 since it has an 8in woofer vs 7in in the 803. I also found the 803 tweeter to be very harsh to the point I wanted to turn it off. Maybe listen at another dealer or have them check the setup. I should add that I listened to the 803’s at multiple dealers and all the same had meh sound. I also own the 805’s (pre-diamond tweeter). It's likely all personal preference though to our own ears :)