For me the default 8.55 is showing that it can use dxva, but when fireing up MPC HC or MP using SAF MPC codec, stuttering viewable blocks e.d. for MKV, WMV e.d.
I've just bought a B206 and I was able to do very few experiments up to now (still fighting with EPG eheh ).
Anyway, SD television works OK (DVB-T) and .ts files play very OK as all SD movies do.
Using Cyberlink H264 decoder I can see some 720p and even some 1080p files (I can perfectly see movies contained here : Watching h.264 videos using DirectX Video Acceleration (DXVA). | My collection of short anime reviews and the fantastic four trailer which is 720p). Coral Reef WMV9 is stuttering both 720p and 1080p.
Strange thing I noted.. I have used the MPC-HC guide at Watching h.264 videos using DirectX Video Acceleration (DXVA). | My collection of short anime reviews and I can see h264 videos perfectly in MPC-HC but when using MPC decoder, mediaportal does not work (in SD-MPEG the dreaded activemovie window pops-up and all is frozen, in HD h264 the movie is smooth but sometimes a single frame from the past appears (usually after a big scene change.. so I think after an I-frame). (Cool fact: accelerated 720p h264 takes half the cpu than non-accelerated "pal" mpeg2).
Anyway, the B206 is very quiet, consumes very low power and comes with all accessories.. it's a very interesting platform for those (like me) who are not very interested in HD right now. The price is OK - I bought it online in an italian shop at 330€. Mine came with bluetooth and wireless keyboard/mouse in the box (they are not listed as accessories).