mike0619:
Cheers,
Any idea if its any better
Substantially, yes - if your PS3 is connected via optical to your 605, then you are not able to take advantage of Blu-ray's HD audio codecs. The connection does not offer enough bandwidth for this.
If you want to be able to experience Dolby TrueHD, DTS-HD Master Audio and LPCM Uncompressed soundtracks on BDs, you need to connect to your PS3 to your amp via HDMI. Then you can either set the PS3 to decode onboard and send PCM to the Onk, or set the PS3 to bitstream the raw audio to the Onk for decoding there.