Anyone else's opinion will be just that -- an opinion -- since everyone has
different ways of learning and different places to start from and different
needs / preferences.
As for AppDev itself, I can tell you it is (or at least was, in the mid to
the late late 90's when I was associated with them as a courseware author
and substitute instructor) one of the largest training companies out there.
Very competent and honest people. One of their strengths was that all their
instructors were working developers / consultants with regional or national
reputations, who actively use the platform they are teaching. Most were
published authors as well.
In my experience the printed courseware tends to be a little thin all by
itself and there was too much reliance on the instructor to flesh it out.
And then the instructor may well add to, subtract from, and/or rearrange it.
I suspect this to be fairly true of any training company; therefore, it's
more a matter of whether you like the instructor than the company. If the
printed materials stand at all on their own that is a definite plus,
especially with regard to exercises and samples.
My advice is to sit through the first couple of video chapters and judge for
yourself.
In addition, whether using video or in-person training, you will retain very
little unless you are actively working / struggling with the concepts
presented. So timing is important too ... if you won't have time to apply
the concepts right away (just before a big project push in the legacy
platform you already know, for example, or just before a vacation) don't
even bother.
--Bob