I just attended a short web session on WorldCat Local Quick Start, because I wanted to find out more about it - I kind of doubt we'll ever be implementing it, and I don't really think we'd want to. It has some features that I think are pretty nifty (although there are other products that could do the same thing), like the ability for users to add their own reviews, create lists of items, save their searches for later, etc. One feature that I don't believe I've seen in other products is the inclusion of information about authors or others involved with the works - in the case of WorldCat Local, this draws on information from WorldCat Identities. I remember thinking that WorldCat Identities was pretty cool when I first found out about it, but I hadn't really thought of it being incorporated into a catalog like that - my brain just can't seem to make those kind of leaps.
As a cataloger, one thing I don't like at all is that all local record edits are meaningless in the WorldCat Local catalog. All WorldCat Local searches is WorldCat master records. True, these can be very good, but some of them aren't so good. I'm sure more of these records have been edited since the beginning of the Expert Community Experiment, but there are still many, many out there that are, well, shoddy, despite, in some cases, having quite a few library holdings attached. Just because a library has its holdings attached to a record doesn't mean that the cataloger(s) there edited the master record. Plus, even with the Expert Community Experiment, there are still records that need to be edited that can't be easily edited by the cataloging community. It drives me crazy when I come across a PCC (Program for Cooperative Cataloging) record that needs to be edited and I can't edit it - and I don't have the time or inclination to write up the needed edits for OCLC or whoever and, if necessary, fax the proof.