12 Mags - Brother, when you do something, you do it Right ! I have not been able to shoot a FN but they provide for the military and if they can survive that, it is a proven platform.
Do not be disheartened because of FNs lack popularity in the US. CZ makes great guns and has the same problems.
The only thing that matters IMHO is - does the gun fit YOU ? If the gun doesn't, odds are you will not shoot it well.
At the end of the day, all that matters is performance. If you get those great groups we all would like to frame, people will start asking - "What is that guy shooting?"