I just auditioned the AK240 at my local headphone shop.
First impressions: Strong everything. Holy !@#$!! It's SOOO much smaller and more compact then pictures depict it to be.
To me it looked like a brick in pictures, but if you see it in person it's really small. Thickness = slightly above 2 iphone 5's stacked. Shorter then iphone 5. A bit wider. Overall my Theorem 720+iphone stack made this thing look like a pebble and that's just awesome that you can get such high fidelity without having to stack 3 devices together. The AK240 will fit in the tightest of jean pockets easily.
Touchscreen sensitivity is flawless unlike 98% of Android devices I have used (S1, S2, S3, S4, S5, Moto X, HTC One, Nexus 4, Nexus 5, Nexus 7). I used to be into tweaking (XDA) with overclocks, kernel/governor tweaks etc.The UI fluidity and touchscreen sensitivity is SURPRISINGLY on par with ios/WP8. I've never seen this from an android device before. I attribute it to the fact that there's NO bloatware whatsoever, unlike the Sony ZX1. I strongly suspect the AK240 OS modules/skin on top of Android is coded in native language, as opposed to running Java in a VM which is how many third party apps on Android are handled. TL
R it's fast, snappy and with smooth transition animations. No perceivable frame drops/micro stutter/micro lags. However keep in mind I didn't do much vertical scrolling, which is where Android tends to drop frames the most in my extensive experience.
We tried Bluetooth pairing as follows:
-Pair with Android phone (Note 3): first try, flawless. You can do mobile hotspot and feed internet from your phone to AK240 via Bluetooth.
-Pair with iPhone 5 (one on ios7.1, one on 7.0.4): both devices get the pair request, but can not connect. Tried everything I could think of, multiple reboots on both devices, factory reset both devices(the store owner had done this before in his attempts to pair them), update firmware on AK240, pair/unpair over and over.
-Pair with Pebble 1 Smartwatch: pairs perfectly, but can't control music from the Pebble for some reason. I strongly suspect this can be addressed with a firmware upgrade on the AK240 if A&K decide to do so.
It's STUPID expensive but I understand why now. I am more than likely getting one. I suggest if you're on the fence about buying one, try it in store if you have the opportunity. Pictures don't do this device justice.