I was searching for YEARS for an MP3 player which would be seen as a Storage Device by Windows (no stupid control program needed, as is the case for the majority of players out there). I wanted a player with an upgradable firmware. A player which would support Vorbis. And finally, I didn't want a player with a proprietary battery pack.
I found the Nex IA, which fulfilled my wish list. The player is very interesting. The problem is, that the company doesn't seem to be serious about properly supporting it. I had (and still have), a boring "clicking problem" between songs. I use MP3 I have made myself, with state of the art methods: EAC safe mode as a ripper, LAME MP3 compressor, with at least preset standard profile, My own CD'S, a Plextor CD-ROM etc... My MP3's are definitely not to blame for this annoying bug.
I had a problem with the master control button. Suddenly, I couldn't lower the volume, only increasing it was possible. I went back to the store, and they decided to change my player for the new model, The Nex IA+. The IA+ can record from exterior line level sources, and the center control button, has a "tighter" feeling. No problem since the switch. But the clicking problem is still there. I watch Frontier Labs website often, and the Chinese version of the firmware is V2.0, while the international english version is V1.3. They don't seem to put the effort or speed in to release the V2.0 international.
Generally, I love this player, thanks to the USB storage device interface. I use good NiMH batteries (2400 maH), with a good charger and battery life (if about 15 hours), when driving a line level device (my car amplifier). I heard a lot of people whining about battery life, but about 99% of the popuplation don't know, that 95% of the battery chargers are bad for batteries. You should seek a Delta V charger which monitors the temperature (if you want fast charge), and it is advisable to charge as slow as possible. Maha chargers are good.
As for the support for Vorbis, I find it stupid to support proprietary Microsoft infamous WMA codecs, and not provide Vorbis, which is open source. Another annoying thing: No support for playlists.