Most likely everyone has tried Plex and streamed some form of media. I wanted to post about the level of ease and stability of using a NAS with Plex's 9.5.2 Server and multiple devices.
Router: Actiontec V1000H
Switch: Trendnet 8 port unmanaged
NAS Teeming Dual 1Gbps --> Router --> Switch --> Devices
802.11N: ~100Mbps connection (Single Band)
RNDP6000-200NAS (Pro 6) Dual 2.6Ghz E5300
8GB DDR2 PC6400
AppleTV 2 (0.10 Beta)
2009 Macbook Pro (0.9.5.2)
2010 Macbook Air (0.9.5.2)
HP Touchpad (Free Beta 0.6.
iPhone 3GS (4.99 on app store)
Nexus S (4.99 on marketplace)
6 (Different) ~12GB (per file) 1080P home videos
Started the streams on all 6 devices within a few minutes of each other.
The results are pretty easy to explain:
-Macbook Pro and Apple TV had no drops as they were wired.
-Touchpad is running beta software (Final coming with server 9.5.3) and took 2 tries to get the media started.
-iPhone worked on the first try
-Android Nexus S had a bit of trouble keeping up over Wifi being the last device to start, so it was switched to a 3G HSDPA Network
SIngle Band 2.4Ghz 802.11N is not enough to run more than 3 streams at once, but more than enough for 1-2.
I was able to view all 6 streams, pause, and play with little issue.
The NAS kept up with out any issues. It appeared to sustain 30-40MB/s for all 6 streams, peaking at 80MB/s.
Load was 7-9, with temperatures around 130F. Memory utilization never went over 1.5GB.
See these screenshots for more information about the loads and the system: http://imgur.com/a/5RC6m
Hopefully you found this test interesting. I didn't attempt to run anything else on the network at the same time, but could have possibly browsed and used subsonic with little effect on the streams. I also have a PS3 and would most likely have been able to DLNA another media file to it, but did not test this at this stage.