Worth a read, but nothing special.
Certainly not on par with the best of the Slytherin!Harry fics, but it makes for a worthwhile read. The writing is well above average and should hold your attention if you don't have anything better to do.
Harry's friendship with Draco is realistic, but it serves little purpose other than being the initial stimulus which drives Harry into Slytherin.
The main downfall of the series is the characterizations. Every Slytherin is the same. There is no variation whatsoever. Chapter after chapter spent reading about a posse of spoiled bigots who don't do anything other than remind Mudbloods that they are inferior gets exceedingly tiresome and mundane.
I give this a 5.5 out of 10, generously rounded up to a 6.