Some v1.2.6 Observations.
New "raindrop" wallpaper. Cute, but I can think of better things to do with the background bitmap.
Settings->Gapless setting: "Close" now reads "Off".
Settings->Advanced->Power Management->Sleep Timer: new setting. Has "Close" for "Off". Go fig.
Settings->Advanced->Factory Reset reboots into Recovery and erases /data and /cache.
Media scanning progress bar, as has been noted already. Scanning does appear to be faster. This could be a genuine speed improvement for some or it could simply be that having a progress bar alleviates frustration. Either way, system processing feedback is always a good thing.
The list scroll bar area on the right may be a little wider.
I'm hearing no hiss or whine from the HP jack while a media scan is in progress. No hiss or whine while paused, nor while playing at very low volume, nor paused at maximum volume and gain.
Stereo separation is noticeably wider than 1.2.5. Those of you hating the 1.2.5 soundstage should be happy -- at least happier -- with 1.2.6.