I have the stock red dot that comes with t9.1 ranger and while it might be a good solution I am considering getting a scope.

On my t8.1/mp7 I have a used 4x30 riffle scope which works well enough but is large and is not illuminated. 

I have thoght about 4x ACOG clones, the tiberius elite scope, general nc star stuff. 

I would like some spotting ability, durability and above all usability during a game.  

If you were willing to spend about $100 and were buying a scope for
shooting first strike what would you go with?  (or would you use a red
dot)