Airsupply,
My choice, even if you only wishing/needing 20x, would be 4x32. Pm me only because I can say more in two minutes than I can write in two hours and we'll make a time to talk
Would highly suggest, if convenient enough, to drop in on a local retailer who carries night force and these particular models, to look through personally. Make arrangements with the salesman to take you outside in real light to look through these scopes. Chances are if its a more prominent sporting/hunting store they will have a wooden stock blank that you can drop the scope into which will also allow for a better experience when comparing the two.