Pros: The sound quality! Powerful amplifier, with an appreciated 3-steps gain-switch
Cons: Battery life certainly could be better, but the sound quality you get makes up for that disadvantage.
A bit of background: I'm coming from using Sony MiniDisc Walkmans, Hi-MD specifically, with their ability to play full CD-quality LPCM, and providing true gap-less playback, aside a sound quality that is way above that of iPods and other typical MP3 players -and I have tried a few of those.
My musical library just keeps growing, the price per 1GB Hi-MD MiniDisc just isn't competitive any more, and lugging around many discs isn't always convenient, so I'd been on the look-out for a replacement for my Hi-MD Walkmans, and ideally even an upgrade in sound quality, since from using Sony MDR-EX90SL's I'd upgraded to the Audio-Technica W5000's.
I'd considered the iMod at one stage, with a large SSD and a good headphone amplifier with a long lasting battery, & that probably remains a solution for those seeking the longest on-the-go autonomy; also the iPod Classic + portable iDACs, CLAS (-dB) / HP-P1 / Go-DAP(-X) / PHA-1, but why support a product, the iPod, that is mediocre in its conception in its first place? Sure the UI is unanimously recognized as intuitive and practical, but for a music player, isn't sound quality the most important? Apple failed miserably here.
So Colorfly has an interesting device, the C4 Pro, but alas no gap-less, and 24bit/192kHz only via WAV, not FLAC, not quite practical.
HiFiMan just has a terrible UI, no gap-less either, and the design just doesn't appeal to me.
Then iBasso came along to announce their first DAP, and touting it as a "reference" one, setting a new high level standard.
Up to 64GB swappable memory via µSDXC, 64GB internal, gap-less, one of the best DAC's on-board, and a powerful amp; the ability to plug my W5000's straight-in without an adaptor, cool. Metal housing, nice.
All that sounded like a truly meaningful upgrade to my MD Walkmans.
So, bought it, and how do I like it?
Built quality is pretty good, not quite Sony-Made-In-Japan level, but very acceptable. 64GB capacity and credits are printed just slightly slanted on the back*, and I have to insert the µUSB cable into its slot also in a slightly slanted manner. I don't mind that, but I can imagine others would return their unit immediately for these little faults. I'm too addicted to the sound right now to bother.
Wow! As the listening mileage grows, all I can say is that I'm very impressed, and get a better idea of what my W5000's really are capable of.
The DX100 is giving me the best sound quality I've ever heard with my headphones. My first true audiophile experience.
The user interface takes some getting used to, but one gets the hang of it after a while. I've disabled all the applications but the music player of course. This reduces interferences and optimizes battery life.
I'll post more in-depth impressions of actual musical comparisons eventually, but so far I can notice more depth in the sound, more impact, the power delivered is adequate, the treble extends higher and ever so smoothly, though still crystal clearly, without fatigue; bass goes lower too, while remaining tight and articulate, and I will hear no more "W5000's are bass-light": if you think that you either didn't bend the metal bands enough to get a good seal, either you won't admit you're a bass-head, or they weren't amped adequately! Since the thundering bass you get here when its called for is tremendous! I was already quite happy with what the EH1 or RH1 could deliver, but this is even more impressive. More bass impact would be too much.
Mid-range is beautiful, nothing special to add; will do more piano listening for this aspect.
Sound-stage, imaging are bettered too; instrument separation is further much improved.
Now, the details, those are amazing! I get so much more out of the music; typical comment, but indeed, I now hear things in the recordings much better or that I hadn't even noticed before!
All these qualities on the DX100 brings you closer to the live sound!
I'm very, very pleased with my purchase.
Disclaimer: You've noticed I'm only a budding audiophile, haven't had other high-end gear to compare to, so please take my comments with a pinch of salt. Just MHO, YMMV.
N.B.: User interface rating I have bumped up a notch since my first rating, since with firmware version 1.1.7 and proper ID3 tagging, album art & tags show up nicely, and the UI operation has become a little snappier.
N.B. #2: Support of 64GB µSDXC confirmed. After formatting to FAT32 it is perfectly recognized by the DX100. 120GB of flash memory at hand, ain't that nice! I will be adding more of these flash memory cards over time since my Norêve carrying case conveniently has a few slots for them, but moreso because those high definition albums do take an awful lot of space up...
N.B. #3: With iBasso's v.1.2.7 FW update for the DX100, the user interface has been much improved: nearly all my albums' cover art is showing up, the battery management is better in that the standby mode is effective, so that it doesn't drain as fast as it used to, and believe it or not, the sound quality has moved up yet another notch!
Thus, I have bumped up the UI rating by another half star!
*After more than six months of very intensive use which translate into a few scratches and dents, I made use of iBasso's excellent customer service & cheap spare parts catalogue & ordered a new backplate, and that one is impeccable. With a new display protection —that I got for free— I also ordered two extra mains adapters: one for in the backpack & one for at my other most visited location. All this was promptly shipped and delivered just as quickly as the DX100 itself via DHL.
P.S.: A few user interface images that show CUE file support:
N.B. #4: Some fall 2015 updates on my usage of the DX100; Support of 128GB µSDXC, provided you format it to FAT32. I now clean, edit ID3 tags rip & transcode all to ALAC (wich has become open source since a couple of years) with the help of XLD & iTunes, & album art display at start-up, playback are now truly flawless on the DX100, & I've gotten used to iTunes & Audirvana+ as music manager & player on my computer, so a unified file type on all media.
More than 3 years after my purchase, I'm still very happy with the DX100. I ordered a new battery via iBasso's customer service & cheap spare parts catalogue last year, it was fairly easy to install & brought the battery life back to normal, lasting around 8 hours.