I did this the unconventional way around – I read it after the series. From my understanding, the series by HBO has taken major plot diversions from George R.R Martin’s books. However, for the first one, which at this stage is all I’ve read, it was pretty accurate and on the mark!
The first book is very descriptive, which was a thrill considering I read it because of how much I enjoyed the series and so it almost felt like I was reading an associated history book. That said, it’s possible I would’ve found the descriptive bits too dense if I didn’t already know the characters. It’s a lot to keep track of. For now, I’m on to the next.