I can`t do without ironsights- addas a great deal of realism for me.
I`ve heard that Vegas now uses ironsights too. If it wasn`t for Steam, I`d have bought that by now.
I saw the gameplay videos of the ironsights in New Vegas, it looks pretty awesome. (Sadly I have not bought the game for the exact same reason)
For as cool as ironsights are I still go with WMK, it has many more benefits to gameplay and I can put a scope on most of my favorite weapons. Plus with FWE you get Shlangsters scope mod that lets you zoom in and out with the scope.
If I may endorse something I had a small hand in, there is also Zealotlees ACR which is a single weapon with swappable parts like WMK plus there is an ironsights mod made just it.