While I have not used it, I do have a copy. So I looked at it.
It does have some things in favor.
1. It uses the new mechanics sequence of momentum before energy, which has
been found to be beneficial.
2. It uses motion maps and graphs extensively which has been shown by
research to be beneficial.
3. It does talk about what is going on microscopically which is essential
to developing a better understanding. So a string under tension is looked
at as being a collection of atoms which can stretch slightly apart. He
evokes the idea of all solid objects as being spring like which is a good
way to develop interaction.
4. He does use bar charts which are known to help students.
It has some things which are not consistent with the research.
1. It does not do the NTN laws in the best order. Interactions needs to
come before NTN3, and both should come before the other laws. The best
order is 3, 2, 1. Just because he used a particular order does not mean
that is the optimum sequence.
The section on forces introduces forces, but does not stress interactions.
While it does stress the idea of an agent and an object, the interaction
must be stressed to improve students understanding. Finally after a number
of chapters he introduces interactions with NTN3 almost as an afterthought.
2. It has the usual bad inconsistent notaion with T being used for tension
force rather than using F for all forces with appropriate subscripts.
3. He talks about energy transformations, rather than energy transfer. The
energy transformation idea makes students think there are different types of
energy and serves as a barrier to understanding conservation.
4. It has the traditional symbols for energy which again lead students to
think of energy as a number of different things, rather than a unitary
concept. He should have used E for all reference to energy, with a
subscript for the different energy storage locations.
In balance it is not as thoroughly research based as if could be. Knight's
book talks about reading the book before lectures, which leads me to believe
that it is again a hybrid book designed to bridge between a research based
approach and a research based approach. The little stories at the beginning
of the chapters may be part of what students may not like about it. The
story about money may impress them as being unprofessional and grade
schoolish. Money is a useful analogy, but introducing it in a cutesy story
may be very off putting.
I used a book for years which was extremely research based "Minds on
Physics" and the administration was always pressuring me to get rid of it in
favor of a conventional text. I resisted until the bitter end when I left
the school. But with that book I was able to get high gain, and I could
lean on it for useful activities.
Unfortunately students will not like books which depart from their
expectations. But hybrid books will still often allow students to be
equation hunters rather than using concept based problem solving. For
example Knight goes part way and only has 3 of the 4 SVT equations. I would
only have the two basic ones, and have students use concepts like slope and
area to solve kinematics problems.
Knight is very didactic, but it does have many of the useful concepts
brought out explicitly. But when it does NTN3 I didn't see all the tips for
figuring out which forces are related by NTN3. While he does state that the
two NTN3 forces can not be on the same object, he does not point out that
NTN3 forces must be of the same kind, so a normal force can not be the
reaction to a gravitational force.
Personally, I would rather have no book, than one that fights me. So from
my point of view Knight is not ideal. I had always heard it praised as
being a research based book, but I never had the incentive to look at it in
detail. Now that I have looked at some of the details, I find it to be a
book that I would at least have to partially fight, and at minimum alter the
sequence from the book sequence.