The old Logitech definitely has more "oomph" in relation to the Logitech UE, for the Logitech UE listens to clear (is longer lie at the Int. Electronics as the chassis), that is less bass and more treble.
The "old" version has preceded the two new boom boxes the track skip and Play / Pause buttons !!
The current model "UE Mini Boom" is touted as a total novelty, as far as the sound I do not think so - in direct comparison, the UE Mini Boom hear more again as the first to Logitech. The UE Mini Boom is loud as similar, and show respect to the UE Mobile fewer heights. The actual innovation is the control by APP, with the help of which you can adjust the sound character (well), can read the charge state (good) - and you can drive from the UEs two - either stereo or dual mono mode.
So each of the three variants has its advantages - as fun music speaker I feel the original version is still the best. You have the player no sound control at your disposal, then the UE Mobile Boombox is more advantageous because the bass is not too much into the foreground - and the improved high frequency response makes the sound appear cleaner. The (current) UE Mini Boom just has the advantage of the App-Control, which does not compensate for the higher purchase price in my opinion - in particular because of the no longer part supplied with the AC adapter !!