Reviews found online can be of two extreme types - never anything inbetween. Either they profess that the item in question either cured their cancer, or the item gave their dog AIDS. This makes the odd useful review rather stunning. Such was the case with a review of The Art of R Programming by Norman Matloff.
It was indeed a very thorough overview of R thus making the book not a very good starter text. If I had to place it I would say that it is a good intermediate reference text. I feel confident that in starting to write more complicated R code that I will find a use for the book as a reference. Specifically I found the section on interfacing R with other code to make your own custom - and hopefully fast - funcitons using C or Fortran. I do wish I had read the chapter on debugging before attempting a few things. The suggestions and examples were spot on for the nuts and bolts of how to get good debugging support out of R and Rstudio.
The only real downside to this text is how loquacious some of the examples are. I read the text on my iPad and it would often be two or three pages of code typed out in the book. This made it a fast read, but I think to really extract the most understanding it would be necessary to type the examples in and play with them a bit. I found myself insufficiently motivated to rise from the couch to do such an activity.