Well I said I was gonna test various firmwares and I did. What's surprising is that I don't really come to the same conclusions as most of you guys.
So I tried Doc2008's New Favorite Firmware Final, New Favorite Firmware Megabass Edition and New Favorite Firmware Surround Edition Final.
I must have wooden ears or something (I tested a couple months ago and I can't hear a damn thing above 15 kHz btw) because in all honesty I can't really tell a difference between these 3. I perhaps could if I switched between two players, but here with the time of updating the rom and all, my auditive memory does not allow me to clearly pick out the differences. To me they all sound airy, dynamic, deep and sharp at the same time. Precise yet non tiring. Also, I can't understand the claims of the highs being shrill or fatiguing with NDFFF, those highs sound veeeeeeery smooth to me.
Now I also tried SU 1.3.3, it's a very different animal. I hope I won't get flammed as it's very well regarded here I don't wanna sound arrogant or anything but I didn't like it. I found it way too smooth, too bassy, lazy sounding, with the high seeming to be cut-off or something and an impression of lacking dynamic. Very analog sounding in a way, but also boring to me. I do understand why it is appreciated because well, yes, it is non fatiguing that's for sure, but it's not for me. I like a sound that is more incisive.
SU 1.4 seems to sound closer to the various Doc2008's I tried. Airier than 1.3.3, less analog sounding, sharper. It's quite good. At one time I didn't remember it was the one loaded and I thought it was NDFFF.
Note : those tests were loosely made, and ran across several afternoons and evenings with various levels of brain and ears fatigue and are by no means the truth, just my truth
In the end I'm keeping NDFFF for now but I will probably keep trying other FW as time permits and do not exclude trying again SU 1.3.3 once more just to make sure.
The conclusion to all this is that it's best to try it all for yourself and make your own opinion ! Your results compared to other's will vary depending on your own headphones, sound preferences, music genres tried, experience, the way you understand and use sound jargon, etc. Changing FW is so easy it hurts, and takes less than 10 minutes...
Edited by caml - 5/27/15 at 9:07am