two way v. three way speakers


I recently heard some magico mini's at a friend's house. They sounded amazing. And they were 'only' a two way speakers, but they filled the room with amazing sound. So now I wonder, what does the additional driver add, especially when it is the same size as the second driver. For example, the SF Olympica III's have two drivers of the same size. I know that third driver adds a lot to the price, but what does it sonically? Thank you all in advance.
elegal
Audio it not about money. Money does not give you a good or better sound. The most important part in audio is that it Always will be a matter of taste. When people prefer a coloured low freq. You cannot say you are not allowed to find it that good.

Audio is about quality. These days you can get a very good sound for not that much money.

There need to be more open information about the good products and the bad. Because those bad products make people react so differently on threads in general.
a 2-way has a simpler crossover. That can more than compensate for the benefits of a 3-way, especially in a smaller room, where you don't need to move much air.
i typo'd go buy piano and harp. i meant i have a harp and piano in the listening room and a professional musician to listen to them anytime i desire. i know what they sound like. this is a for profit hobby and the idea is to make people constantly seek and spend more and more. i was down that rathole. why do you have to throw in the jab re set amps? it is like pot, the big drug cos. despise pot cuz it will cut into their profits they think. same with audio gear industry and old school full range drivers and small tube amp. with new advances the sound rivals extremely costly gear and fits in small spaces with few cables. all this crap thrown out there about all these tiny details is just pointless as it just leads to more tinkering, but this is why it is a pasttime and not an end purchase. i now use my money to buy great music well recorded.
I used to have 3-ways with two 61/2 bass drivers and an identical mid driver. Now, I have a single 51/2 driver in a transmission line speaker with a parallel sub. The first ones were 91db and the current ones are 95db. When I go to my dealers showroom and listen to the ones I used to own, I can hear the crossovers and interrupts the musical enjoyment. Once you go crossoverless, it's hard to listen to more filters.