I think this feature will be particularly useful for slower machines (i guess even p4 would be slower in case of transcoding at HD)..i would assume in some way it would help avoid jitter (apart from slow play) on slower machine..In my case, I have converted my older linux machine into NAS and all my media storage lies there. I run PSM on that machine. For my kind of user
..which i guess would be quite many..will benifit from this.
Additionally added advantage of improved seeking support etc. I am not an expert here so can't say about technical complexity..etc... but this should be bring competitive advantage, if this somehow address the issue of slower machine.
If PSM is running as service then i guess PSM start up time shouldn't be an issue.