Not only improvements over NP1100

One star deduction for the small screen (less than the NP1100 !!) and small letters, a second star deduction for insufficient support added for VBR MP3s, the small to display the clock, and the lack of support Samba.
I think that currently no better device on the market. Many have built-in speakers, you may not need (stereo), and no outputs, there are some who still have smaller displays, or other that are far too expensive.

Pro:
Fits perfectly to the application scenario - delivers music from the network (Internet and local LAN) to a stereo / amp.
Sufficient outputs (analog & digital), I run it currently analog and the sound is great.
Are more familiar with MP3s with VBR than predecessor NP1100
Standby mode (Better remote control NP1100 (OK and Back button)
Network connectivity and wireless LAN (not self-evident; a series of devices that have come on the market do not have a cable input more - see Xoro)

Con:
Color screen is a bit small, smaller than its predecessor NP1100
The ingenious feature of NP1100 - where the currently-selected item has been enlarged - is gone.
That and the small display cause the NP2500 can only be operated from relative proximity - about 2m. The NP1100 was operated from 4m distance!
Does not support completely the VBR MP3s (variable bit rate). It can happen that will cut off a small piece at the end of the song.
Clock is lowercase -> not visible from the distance
Clock is "only" a Screen Saver -> 5W power consumption for the clock ... a bit too expensive for a clock!
Only supports UPnP, so can not the music from a Folder is via CIFS / Samba geshared. If you have any problems with the UPnP server have bad luck.
Perhaps as a result, it can for example make any other order as the server what gives him (it can not sort title either by name or track ID).