Certainly "It Never Snows In September" is not written a la Ryan or Ambrose - so if you need your history slick and stylish this is probably not for you - but it is readable and fun to read. Kershaw is a military man by training not a writer like Ryan or Ambrose and given that fact "It Never Snows" is actually a quite good read. It's not simple a dry treatise of facts, there is heart and sole. If you want to know more about Market-Garden and the Battle of Arnhem, and want to have fun learning about it, I suggest combining "A Bridge Too Far" and "It Never Snows in September" as a tag-team. These two books alone will give you your fix and them some. "It Never Snows" is currently out of print and getting a copy will cost you (unless you can find one in a library somewhere) but it's worth every cent!!!
Kershaw takes a logical method of breaking the battle down into pieces, and has added new insights to each section of the battle. Some parts are slightly sketchier than others, but I suppose that's due to the lack of available information. The book also has several series of photographs, though Kershaw takes the somewhat annoying tack of describing each photograph in the text as well -- one picture is worth a thousand words. Lastly, the author disputes the theory that the British 1st Airborne would have held the Arnhem bridge if they had landed closer to it.