A discussion on the Bose is always an interesting exchange of view points, so here is my take on it, and which expands the post I made on the PA2x thread.
The L1 was designed to allow a performer to be easily heard anywhere in the venue, and it also allowed the speaker to be set up to give optimum performance with whatever the performer was playing, in addition the L1 can be placed behind the performer so as they can also hear what the audience hears.
With conventional speakers you also have to have monitor speakers for the performer, as in most cases the main speakers have to be set louder then the L1 to fill the venue and so have to be placed in front of the performer. (Having the main speakers behind the performer would just deafen them, and give them no idea of what the audience is hearing)
As most of you who have read the above will have noticed, a problem occurs when using a keyboard/Organ with the L1 because a keyboard/organ produces the sounds of multiple performers, and so the L1 can no longer be set up for individual performers. (This is why a single L1 sounds like a wind up gramophone horn (With a sock stuffed in it) when used with a keyboard)
Fortunately virtually all keyboards these days are now stereo which spreads the performers out, and so providing you have 2 L1s (Back to stereo again) you can set the EQs independently and so get a much better balance. The downside (There’s always 1) is that if you change to a different style of music you need to reset the EQ settings of both speakers to match. (Otherwise the Gramophone returns)
Incidentally if you look at the professional keyboard/organ players that use the L1s, (And there are boat loads out there whether it be at a Club, Concert Hall or Stadium etc) they always have a minimum of 2 L1s. (If more are required they always go up in even numbers)
L1s set up correctly (And adjusted during a performance) can give a superb quality of room filling sound that other speakers have great difficult of achieving, however it does require more input from the player.
As with all things, only the player can decide if the L1s are suitable for the venues that they perform at.
From the above, you can see that while the L1s can give a superb sound, they are not the Be All and End All that some people seem to think they are.
Hope you found my ramblings interesting

Bill