[Mydriaze]

I'm new to koi and i'm thinking to buy a Raspberry Pi in order to run Openelec (To be honest, i'm hesitating with a 150 euros devices such the Open Hour Chameleon).
I can't find many information or video on youtube about the graphics VideoCore IV in the B+ version: Is the 25 or 50 gb Blurry running smooth on the raspberry pi and openelec?

I assume you are talking about raw ISO files, rather that using a Blu-Ray drive?

Yes, I am able to play 50GB raw Blu-Ray ISOs on my Pi with OpenELEC.

It depends a bit on your setup.
If passthrough is supported by receiver it makes it easier.
Playing from a locally attached hard disk makes it easier.
NFS is better than SMB for when network attached. Mounting NFS share from OS rather than kodi GUI makes it easier.
Playing an mkv remux (without reencode) of the ISO makes it easier.
Overclock makes it easier.

You can get away with a couple of above being non-optimal, but if too many are you may struggle.
Perhaps explain your setup and I'll say if it sounds likely to work.

Thank you very much for your feedback and having taking time to answer my question.