Alright just like to list my experience with the DX50.
I received my DX50 with V1.2.2 (Batch 6 from mp4Nation) and the player worked fine from day one. I never experienced any glitches. I upgraded it to v1.2.3b like many of you and again followed the instructions from the readme file and all went without any problems. None. I won't comment on the sound signature changes because it's very personal and dependent on the IEM/Headphone used. I did notice an increase in the lower frequencies but was happy with the v1.2.2 too.
This morning I decided to try the latest firmware, v1.2.5 and again followed the instructions and my DX50 upgraded without any hiccup.
Here're my observations:
1- I have about 4.5 GB of FLAC files on internal memory. After the Upgrade / Factory reset has instructed in the Readme file and my music files are still on the internal memory.
2- I have an 64 GB SD card with a mix of FLAC 16/24 bit, MP3, APE & WAV files all organized in Artist/Album folders. This card is almost full (~58GB).
3- On my first scan after the upgrade it took exactly 5 minutes to scan 4.5 GB internal + 58 GB External. That is pretty good in my book.
4- On power on the DX50 take about 5 second for the quick scan. That is good too.
5- The Gapless option is set to 0 and I don't notice any missing note. The song start playing from the first second.
6- While pausing a song it still take 1/2 a second to pause but un-pausing is instantaneous.
7- The player is noise free with my IEM's (lower Impedance are Sony XBA-3) on any gain level. Get some cellular interference sometime but that to be expected.
In all I'm very impress with this little player. It sound amazing with all my earphones & headphones that I have tried so far and the battery life has been reasonable to me.
This was just my observations. YMMV
Edited by Twinster - 11/17/13 at 9:13am