It *is* faster, using StringBuilder as you suggested.
Other improvements are listed in the ReleaseNotes.txt file in the distribution, which are:
- Added support for Unions and choices (these are represented as embedded objects in Java)
- Added support for defining restrictions to an attribute in the mapping metadata. This is required
for marshalling union attributes.
- Change to application-driven transaction handling (as opposed to doing this in an atomic thread)
- Support for the newer RFC 6241
- Handle varying device capabilities more gracefully
- Simplify asynhronous notification handling
- Handle multiple nodes as notification payload
- Improve performace in data reception over the wire (thanks to Jimmy Armand)
- Allow for SSH subsystem other than "netconf" to deal with non-standard devices