Here the following is important:
- Stereos can be addressed via AirPlay from iPod, iPad, iPhone or Mac / Computer
- Printers are available only on the network
- AirPort Express does not replace the AirPrint protocols to address the iPad the printer
- AirPrint for iPad via an AirPrint printer required
The AirPort Express can be used as follows (with all variants AirPlay works):
- As a standalone wireless access point with a private network name (own wireless access point to the network)
- As wireless Reapeter (extends the existing Wi-Fi network)
- As a wireless bridge (connecting to an existing wireless network and binds via the Ethernet port, a network-enabled device to the network)
When the AirPort Express is connected via a network cable, then, the new version now additionally an Ethernet port, making yet another device can be brought into the network (Blu-Ray player, television, game console, etc.). This port can also be extended to a switch.
The new design is in my eyes a significant improvement, since the old Express was always tied directly to an electrical outlet (which could be solved by an expensive extension), and thus the freedom of movement very limited.
Whether the simultaneity transmitting 2.4 GHz and 5 GHz provides real noticeable difference in performance, so iPhone's surf separate from Mac's and iPad's Wi-Fi in, I'll probably see / feel only in the next few days / weeks.
CONCLUSION:
All in all, the new version for me a significant improvement. I am so happy with the new version, which I consider my current possibly 2. (old Express) to replace.
EDIT from 19.12.2012:
Since iTunes 11 communicate / synchronize MacBook and AirPort significantly faster together.
