I finally finished my A Song of Ice and Fire re-read today with A Game of Thrones.
One thing that struck me is that the first book is really fucking fast paced compared to the rest. Every chapter is important and moves the plot along, the prose is much simpler, more focused and functional, a huge chunk of the characters are together in the story so it has a simpler structure, and there's way less detail given on historical events/background characters. It's a much simpler novel than what followed, focusing on a very easy, digestible conflict between the Starks and the Lannisters.
Think the book is a classic, but I'd say I prefer Martin's writing style in A Clash of Kings, A Storm of Swords and A Feast for Crows. In those books he gave much more detail, was slower, and concentrated more on atmosphere. I actually hate using numbers to score things, but I'm in a lazy mood today so I'd rate the series:
A Game of Thrones - 9/10
A Clash of Kings - 10/10
A Storm of Swords - 10/10
A Feast for Crows - 9/10
A Dance with Dragons - 7.5/10
Books 2 and 3 are arguably the best fantasy I've ever read, Book 4 improved HUGELY on a re-read, and ADWD was obviously several drafts away from completion.
Love this series. Gonna check out George R.R. Martin's other novels next, and fantasy-wise I've started Joe Abercrombe's The Blade Itself.