no...I say use the undocumented stuff whenever it's needed.
technically sp_MSForEachdb and sp_MSForEachTable are undocumented and unsupported, but widely used.
many times, MS is calling something an "undocumented feature", but added needed functionality, but without the official need to support it.
officially supporting it costs developer and support time, so it's often much easier to add a functionality, declare it unsupported, but effectively resolve an issue anyway.
--help us help you! If you post a question, make sure you include a CREATE TABLE... statement and INSERT INTO... statement into that table to give the volunteers here representative data. with your description of the problem, we can provide a tested, verifiable solution to your question! asking the question the right way gets you a tested answer the fastest way possible!