Tim,
I tested both the Bose Soundlink Mini II and the JBL Charge 2+ and settled on the Bose. I use it with an iPad Mini 2 and a 7th gen iPod and it pairs as soon as it's turned on without fail, whereas I found that the Charge 2+ sometimes had to be reminded to pair with both devices. I've been very pleased with the Bose. I have not used AirPlay so I can't comment to the differences in operations vs. Bluetooth, but I can say that the experience with Bluetooth has been smooth and solid. As with any BT device, pairing gets spotty after you get over about 20 feet away, less if there are walls between your device and the speaker. I've owned the Bose for 3 months, so I can't say too much about reliability except that it has operated flawlessly in that time, and that its quick recall of devices on its BT pairing list was very impressive compared to other speakers I've owned (a Logitech/UE mini boom also did well in this category, and both were better at BT pairing than the JBL Charge 2+ in my experience). I agree with you that the sound quality is unmatched at this price/size point; that was another reason I chose it over the JBL even though the JBL had a bit louder maximum output and slightly more bass punch at near maximum volume. There is an outstanding review of this speaker that compares its measured sound output to the JBL and others at this link:
http://www.oluvsgadgets.net/2015/06/review-bose-soundlink-mini-ii.html
The review is extremely detailed and does discuss the Bose's tendency to reduce bass at maximum volume when compared to the JBL. In side by side comparisons with the same music played from the same iPad and an iPod, I did notice the difference discussed there, but I didn't find it to be of any significant impact in music I listen to (mainly classic rock, classical, and movie soundtracks of a "classical" style - John Williams, James Horner, etc). If your music taste is heavily dependent on strong bass at loudest volume, I'd say the Charge 2+ might be a better choice for you, but in my experience the levels and clarity of sound from the Bose at all volumes were better for my listening tastes. A caveat about the JBL design that concerned me was that the drivers are side mounted and exposed; they are supported by the interior frame and are mounted in a rubbery material that allows them to resonate, maybe helping with the slightly better bass performance, but the design seemed very vulnerable to me - stuff it into a bag with a pen or keyring at just the wrong angle and it seems like it could get torn. The Bose on the other hand is built like a tank and seems very durable by comparison.
I hope this helps you get the best sound experience. I don't think you could go wrong with either the Bose or the JBL, but having tested both I found that the Bose sounded better and had a better design for durability.
