This book is soooooo good. I read Pfanz Day One and Martin's July 1st back to back, and without a doubt, Martin gets the nod. Pfanz book is wonderful, don't get me wrong, but it reads too matter of factly and there weren't as many of the analytical remarks I was expecting. However, Martin provides many more details, but also a lot of the analytical questions and answers that makes reading about the battles interesting.
Maps are excellent and numerous. As usual, a few more wouldn't have hurt, but I'm happy with the ones they had.
I read the "revised" version so I had no troubles with the editorial mistakes like some others. Just make sure you get the revised copy.
The flow of battle is a little tricky to handle because you have multiple troop movements, engagements, important orders going on at the same exact time. Martin's style is to stick with one "action" all the way through. For instance, the action at Barlow's Knoll leads to Kryz's moving in reenforcements, which leads to Union retreat on the right, which leads to Coster's stand, etc. Then he goes back and handles the entire action of Pender's action which was happening at about the same time. I prefer the style that jumps around from section to section so you can read the actions in a chronological order, but Martin handles his style quite well.
Simiply put, the amount of research, details, and nuggets of info (i.e. stories of valor, etc.) are excellent and well worth the price, and make an excellent addition to your civil war book shelf and most certainly your GB collection. This book is for the more advanced student, so beginners are better off starting with an entire campaign or battle book (like Trudeau or Sears) before tackling the micro study.