I really rate this tactic. After dominating my first season with my own tactic for Arsenal, the AI decided to crack it - rendering it nearly useless.
I like tactics which reflect how modern football is played at the highest level, both 451 and 4231 seem the most commonly used, and this tactic is a real treat to watch.
The use of exploits in recent tactics have somewhat cheapened the experience of FM for me, but this is completely realistic (aside from the corners, but everyone uses near post) and plays great, controlled football without leaving you feel like you're invincible.
Well done mate, just wish you'd have made it sooner!