extra $ 500 ....??
The stock dimensions on them are different - drop at comb is about the same on both - but drop at heel is 1/2" different.../ so if you haven't shot them - how do you know which one fits you ??
They are different animals ...Montefeltro is the entry level Benelli at about $ 1269 list ...but is an Inertia operated gun ( and you're going to get a lot more recoil out of a wood stocked inertia gun vs a gas gun like the SX 3 wincheter....( and since FN / Browning owns Winchester ...the SX3 and the Browning Silver series are virtually identical ) ...so I don't know why that gun isn't in your mix as well....but the SX3 depending on which model you're considering lists for about $ 1279 ....so they're about the same price.
Have you looked at other Benelli models ...??
Have you looked at other gas operated guns ....like Rem 1100's, Berettas semi-autos, the Browning silver series...??
It isn't important which one I'd choose ...it depends on what fits you / not me. But I like the Benelli's in an Inertia system - in a synthetic stock with their comfort tech recoil supression system in them ...vs their wood stocks ( that cannot have the comfort tech in them) ...because the Inertia guns all shoot really clean. Most gas guns are a little heavier ...but lighter recoil ...and if you're not shooting it in competition ...say 200 shells a day or more ...then cleanliness of the action may not matter to you.
They're both good durable guns ...no downside there..../but so are the others I listed...