I have two 3-9X40 FF-II's and could not be happier with them. One sits on a 338RUM and the other on a .270. Neither of the two have given me any problems what so ever.

Having said this.........
If you are comparing a Burris to a Nikon monarch you should really be comparing a Burris Signature select instead of the FF-II. Even though Burris claims that both the monarch and the FF-II both have 95% total light transmission.

The signature select 3-12X44 would be my choice over the Monarch.