lol the link says "sorry no matches found" :)
The easiest way to see the difference is to search "dynamite chalice" in the R2R search and then google "dynamite chalice Reef2Reef". The Google results come back with specific pages with both keywords being equally relevent. The R2R searches do not seem as relevant to both keywords and seem to be highly dependent on date (although I think i can change this...). Searching titles might narrow your results but still won't give you back results that are page specific.
I do need to play around with it more, but I thought the inability to search specific pages was big b/c some of the best threads are very long and pic intensive.
Of course of lot of a searches ability to find things is also dependent on good tagging also and that is up to the user. Plus my research style may be very different than others.
I do think it seems to be working a lot better and I'm not necessarily saying it needs to change (i mean, using both google and R2R search gives pretty complete results back). I'll use it some more and give some additional feedback if any.