Tony, I don't want to beat a dead horse (this topic), but I did want to clarify one point that may be overlooked in this debate.
First, let me say - I LOVE stereo - I have used it long before it was fashionable, and I enjoy all the perks it brings to a tone. With THAT said, I am a performer, and my audiences are rarely right in front of me, exclusively. They are spread out in different locations throughout the rooms I perform in. Even the so called "sweet spot" on the dance floor is usually to large to let everyone enjoy the same great tone at a great level, so the Bose people (geniuses) found a way for an entire room to hear high quality, balanced sound no matter where you were. This current setup has the quietest on board speakers I've ever owned, and I miss the "in my face" monitoring that I'm used to, but I'm trying to adjust to that. The stereo tones that used to fill my ears are now, so lost in the din of the room, I'm just happy that I can fill the room and not sound overpowering to any one spot, like conventional speakers do. I won't do brand bashing ... instead, I'll include ALL stereo systems as my test subject:

1. No conventional horn/woofer system is capable of the even projection of a line array, and that is why the Bose is so effective in it's quest to fill more space with sound.

2. Horn driven tweeters "throw" the sound at a quicker rate than a cone speaker, so the result can be harsh if you're in the front line of that horn. This has always been the case - it's how they are designed. They push the sound out quickly so it carries further. If you're right up front - you get the loudest, most damaging frequencies first, before they attempt to race through the room to reach the back wall.

3. Entertaining is all about connection with the audience, and in that respect - the melody, or voice is the most important way to establish that connection. For singers, we need to reach the audience with words that touch them, teach them, entertain them, and hopefully, won't annoy them. In the past, when I had the big rigs - people would take one look at the speaker cabinets and move to sit somewhere further away. They were aware of the risk and annoyance, I suppose. For a background music situation (I call it musical wallpaper - people appreciate it, but it's really just hanging there in the background), it's even more important that the sound is even and unobtrusive. No one eating dinner wants to be forced to listen to anything, and if a performer or musician is smart - they will do everything they can to enhance the evening, and not detract from it's pleasures.

4. Concert venues are a whole different story. The size, shape and audience expectations are all factors in what type of speakers to use. In my small world of local entertainment - I have found that repeat business is the key to my success. Please them and they will hire you or come see you again and again. I love using my QSC K12's in Stereo with my Mackie mixer - it's a tight, balanced sound and when it's called for - it's awesome. It's just usually overkill. Smaller systems like the Stagepass and Passports, just don't have the same clarity and punch. They sound OK, and they are reasonably portable, but they fall in the middle of the best to worst scenarios for my money.

5. So, how about the 2 Bose tower setup? Well ... I tried it, and I found a situation similar to Yamaha's phase cancellation happening. These systems fill so much off axis that they were dropping out right in front of me. I suppose placement is key, but there is not always the luxury of alternate placement in may "small time" situations, like the kind I make my living in. Simply put - Less was more in my listening test. Bose systems require a mindset change - the performer needs to adjust their thinking to a new generation of sound reproduction. In an iPhone world, the old Princess phone is simply outdated.
Sure, the ads target the solo performer, but that's because so many bands ore out of work. It's the soloist who has moved to the top of the musical food chain, and it's just smart business to know your market... much the same way that keyboard manufacturers make their keyboard sound the best TO THE LISTENER who bought it. They aren't even concerned how you're going to amplify these products. They want the user to be happy with the sound, and that's usually accomplished.

It's been said many times that all these instruments are tools, and we need to use them to our advantage. No one at Yamaha can possibly know how to tweak or organize a keyboard to facilitate MY style of entertainment, or yours ... or anyone's. They make a product for the masses, and they make a profit along the way. MY profit comes when my audience is happy, I'M happy and the bills get paid.

It's really funny how so many get their panties in a bunch when this topic is discussed. It's not like curing cancer, or healing emotional problems ... geeze - some of the responders need to lighten up about the whole topic. It's OK if you disagree, it's not OK if you provide false information to an inquiring population. Many of the readers here are not professionals and they base some of their buying decisions on what we have come to learn after years in the business. Let's try to remember that and provide unbiased, practical information that they can use. Of course, we will always interject our opinions; it's human nature to blow one's own horn sometimes. I'm trying to listen to other' horns these days .... if they are playing a worthwhile tune - the others ... well, that's just noise, and I'll tune it out.

In closing:
Stereo is not better.
Mono is not better.
It's the performers job to KNOW when to use what, and how to use it to the advantage of the room. The room is the boss.
I'm going swimming for a bit ... anyone want to join me? It feels like 100 degrees outside .... Cannonbaaaaaaaaaaaaaallllllllllllll!