I’ve been using RDA for original cataloging since October 2012 at MPOW. With authority records things have been great. There is a lot more flexibility to add and not add things. One hangup is the transition period where records need to be evaluated. Some weirdnesses I’ve encountered have been titles of nobility see:
100 1# Vitzthum, Wolfgang, $c Graf.
Other issues include media types for streaming media. Actually digital files in general are handled poorly. Everything needs a carrier. What exactly is the carrier for a file that is sitting on filesystem in the cloud?
338 ## other $2 rdacarrier
or perhaps if it is published:
338 ## online resource $2 rdacarrier
The file characteristics get handled elsewhere; not a terribly horrible thing, but not exactly intuitive.
More thoughts later.