Hi all.
Just to let you know where I am. I have upgraded to the 1.5 version of the firmware, mainly because I wanted to use a dictionary.
I have found that the pages do seem to turn faster (you were right crusader, thanks) and I can now look up words and use the modi feeds again, just like on my PDA.
I think the epub formats did look slghtly better than the mobi formats, but its no deal breaker.
I now use mobipocket to copy books onto my opus. I do not have loads on there yet. When it copies them it just puts them in the main directory, and I move them into folders with the authors name straight away. This means that the metedata is not a big problem, and I can't say that I have noticed any changes.
No freezes before, and no freezes since the change (only 2 days ago) so overall I would certainly recommend the new firmware, and could also recommend the opus, based on how its been for me personally.

Only had it 4 days and a firmware upgrade released
Gray.