Headlines:
Very computer literate.
Mezzmo is on two of my self-built servers (Quad Core i7-920, 12GB RAM & Quad Core i7-2600K, 16GB RAM).
MKV source movies on RAID-5 16TB DAS, each server has seperate DAS.
PS3, and both servers on gigabit Ethernet network segment.
Have a self-built HTPC with VLC installed but is over 802.11n, which is bridged onto the gigabit Ethernet network segment.
MKVs are all via Handbrake, and is encoded as H264 and AC3/DTS/DTS-HD pass-thru.

Observations:
MKV files play fine on the HTPC over the network including BluRay encoded MKV files.
MKV file playing on HTPC consumes well under 1% of the network bandwidth (just about hits 2% for BluRay MKVs).
Same MKV files on PS/3:
Audio plays without fault, but video speeds up and stops (stutters).
Exhibits behaviour whilst *and* after transcoding.

Not really sure where to proceed from here.
Re-encoding library = not an option, there is 12TB of encoded movies.
Should I build more HTPCs and ditch Mezzmo?