I want my writing to be faster while taking notes in meetings and slightly obufiscated if I drop my journal somewhere, it still needs to be interpreted by me years or possibly decades down the road, or by my successors after I'm gone.
That means that I needed to use teeline over Gregg or Pitman because the ladder are designed for quickly transcribing while you know the subject matter, and that's if you really approach those shorthand notes taken after decades can be extremely difficult to interpret back to English words.
Teeline is grounded in the English letters themselves and so as long as you're consistent with your rules and or consistently inconsistent with your house rules, then someone who learns to interpret a few of your words can slowly but surely unearth all of your words.
A decent web intro: http://realerthinks.com/teeline-for-the-curious-a-story-of-l...
A text on some general rules (intermediate level?): http://natashacspencer.blogspot.com/2010/10/introduction-to-...
A searchable dictionary, good as a reference: http://realerthinks.com/a-searchable-teeline-dictionary/
I also bought the "The Teeline Gold Course Bk". It's good.
Another one which I bought (used for a few dollars) but not yet opened is "Teeline Gold Word List".