Teacher's Manuals to casebooks: how important are they?

When I first started teaching not too long ago, I didn't place too much importance on how good the accompanying teacher's manual was in selecting a casebook.  I kinda thought, perhaps foolishly, that I was familiar enough with intellectual property to answer the CB questions myself.  Also, to be honest, none of the teacher's manuals (as I recall) really stood out as being comprehensive in coverage -- meaning that few, if any, actually provided answers to all of the questions asked in the casebook (at least on my limited sample).

Flash forward to today:  My view on the importance of the Teacher's Manual has completely changed.  This year, I selected two "new" casebooks to teach, one in torts, which is outside my usual area of IP.  The Teacher's Manual for the torts book is, put simply, amazing.  Answers to nearly all questions, and detailed, yet succinct briefs of all the cases.  The CB for the other class (an area of IP) is great, but the Teacher's Manual is very, very thin.  I manage OK without a detailed Teacher's Manual, but I often find myself wanting one in that class, too, even though I am pretty well versed in the area.  It can only help to have the opinions of casebook authors in discussing Notes or Questions in class.  And it will save me much time if I don't have to research something in the Notes that seems ambiguous.

Here's one more reason why Teacher's Manuals are better if more detailed:  it forces the casebook authors to answer their own questions, some of which are easy but some of which may be difficult.  I am writing the teacher's manual for my International IP casebook right now, and, although it is a huge pain in the neck, I know that a detailed Teacher's Manual will help others understand exactly what my coauthor and I were asking.  No guessing game, no hiding the ball.  A prof can pick and choose what to read in a detailed Manual, but at least there's stuff to pick and choose from.