If you've ever had to setup and troubleshoot NIS+, you'll know what a nightmare it can be and quite frankly how unreliable it is unless you're 100% accurate with all your configuration and settings and really know what you're doing. Well, you'll also be pleased to know NIS+ is also finally DEAD!!!
Sun have been been advising that NIS+ will be removed from a future release of Solaris for quite some time in the various docs on docs.sun.com (like the Naming and Directory Services guide which deals with setting up NIS+) and they've finally pulled the plug.
NIS+ is no longer in OpenSolaris as of build 130 (snv_130), so if you're running NIS+ AND are keeping up to date with OpenSolaris or are planning on migrating to OpenSolaris and are still using NIS+, now's a good time to consider migrating to LDAP or to the less complex NIS.
Update: I forgot to mention the PSARC (PSARC/2009/530) and CR ID (6874309) so you can track it down/monitor yourself.