I'm also finding about 7-8 hours of battery time playing 16 and 24 bit files.
Ponoplayer makes the home systems sound much better too, so it's smart to leave it's charger by your favorite home system. Makes my stock Toyota/JBL car system sound amazing, best I've ever had in a car, and I've had lots of car systems. Huge upgrade from CD and mp3, no question. Will take standard car charging, but does not ship with car plug.
Standby time is at least a couple of days, but I have been trying to shut mine down since it reboots so quickly. Shutdown takes 0:02, startup takes 0:25 on mine. It does do a weird blank screen about 6 seconds into startup, but this is still early firmware and a v1 product, so it's minor and maybe something in Android they can't avoid.
PP can get pretty warm after a few hours but it doesn't seem to be concentrated or at dangerous levels. I had mine in an inner coat pocket for hours so it was not ventilated at all.
I haven't heard the Fiio's or Sony's, but I'm having a hard time believing they could sound better than the PP. The discreet analog section is pretty impressive, and we already know it has a nice DAC. It's the widest, cleanest, and most realistic digital I've ever heard. And I'm still running unbalanced out of the mini jack. I haven't used line-out in a critical way yet. I am waiting on Monoprice to do balanced headphone cable then I'll upgrade that.
The lack of distortion, especially the kind that affects soundstage and reverb, is impressive in PP. Since other devices have this DAC I think the valuable IP here is the analog stage, and the focus to deliver an iPod-like experience without any useless features.
The focus to just play music and to avoid every attempt to distract from the music playback, to avoid everything that requires radios or clouds or apps, I mean, it's purity is impressive. It's the perfect DAP if you want to sound the best without being that guy that spent way too much for something he can barely work, something that just replicates something else. It's simple and easy to love and sounds amazing.
It's at least as good, and as important (to me) as the iPod was for it's time. It basically is the iPod, circa 2004, with a high-end audio chain for under $500.
Now we need more music at 24bit, asap, and I'm buying music again. The Ponomusic store has been growing quickly, but the hi-res offerings are still slim.16/44 FLAC sounds pretty damn good on PP, though.