Looking for advice, war stories, comments, etc on which system I should purchase. I use a drummer with a watered-down drum kit for acoustic shows, and the only thing we ever mic is the kick drum. The whole set up is 2 vocals, an acoustic guitar, and a kick drum as far as the PA is concerned.
I have heard nothing but good things about the K12 for use in a small to medium venue. I would imagine that a 18" subwoofer would make the kick drum stand out more than the K sub; however, you mentioned that you play at low levels... a K sub might just work then.
Always get more than you think you need - especially sub (so long as more output does not give you a loss of quality).
I've heard few Bose products that I thought sounded good, and of those that did, all could be bested by something else that was less expensive. IMHO too much of the purchase price of a Bose product goes into promotion and profit instead of product quality and performance.
The QSC product is far more flexible in its use. I also agree that Bose's corporate byline should be "better sound through marketing," but to be fair to the L1, there are a couple uses where it is okay, even pretty decent. The problem is that when the L1 is not well-suited for some application, it REALLY doesn't work well at all.
The L1 is great for background music playback. It's also fine for low-volume acoustic work where you have an acoustic guitar or two and a couple mics in a small, low-volume environment. It does not do well in any live environment that's in any way louder, or which has more than a few sound sources or inputs.
The K-series on the other hand is a great product that can grow with you with the addition of subs, and it will do all the things the Bose does and many more.
I would say that if you're miking the kick drum, you're already out of the sweet spot of the Bose and need something more substantial.