Let me second that opinion
Due to job change/relocation, I transferred my UA 1K to Delta, but they would only match it with GM for that first year. Also, as a frequent traveler to Asia, DL is absolutely pathetic, and their only partner to APAC is Korean Air, not exactly Sin. Air or Asiana. To Europe, DL has a few partners, but UA has even equal set of some.
If you have a choice, don't do a thing.