Well I just picked up a couple of HP Elite 8300 SFF boxes which will be replacing the Microservers. And cheaply. Like $75 per box for something that is 9 months old - we sold them to the client! A big step up as they are i5-powered, and will do 32GB of RAM each while maintaining the low-profile P410 RAID and NC360T network card.
I had hoped to fit two 4x2.5" cages in them but there is no space for that malarkey unfortunately. One will fit but the second really is only for a 3.5" Floppy or SSD as the SATA ports on the mobo impinge on the space. I might see if I can get an external drive box with a SAS connector and just route a cable out the back so I can maintain my 3TB Toshies. I would even prefer something that I could share with box boxes (dual SAS connectors) and do some shared storage which would be awesome. We have a client with a Promise SAS array like that but we are talking thousands for that box.
Anyway - PLEX JUST WORKS. The transcoding is shit - I agree. But that is because of the asthmatic CPU in the Microserver, not Plex itself. Generally anyone with low end hardware like this will convert the file to the required resolution on their desktop and save that to the storage and stream it native resolution. I am pretty sure the Microserver can handle that.