My Def's showed up. They will not be leaving my house, probably ever. I haven't heard the Wilsons, but I'll compare with crossover'd speakers in general.
Yes, there's a big difference. Not having the signal smashed through a complex crossover, divided up, and sent to drivers with varying properties produces a whole, organic sound that is at once warm and accurate. The inconsistencies that are (speculating) inherent in the typical multi-way design and construction processes do not exist with the Definitions, or Druids for that matter.
The brain is released from the chore of hearing these different voices and integrating them into one. Since the drivers are identical and parallel, the music reaches the ear already as one whole sound. Based on my experience with multi-ways, I don't think this is possible with drivers of different sizes in different locations made from different materials.
Their bandwidth is limitless, which the Wilsons should be. The presence region is more forward, and Treble and bass are not tipped up like other hi-fi speakers. Thus, they may not be the best for some rock music. But, I wouldn't change the tonal balance one bit, as it is NATURAL.
And, the sum is MUCH more than the parts. Anybody in Seattle wanting to hear these, let me know. These speakers WILL catch on.