pros: small to midsize commuting loads make *MY* bikes handle less poorly compared to rear loads. Your mileage may vary.
cons: With a front rack set up you usually have less versatility for the dollar compared to rear racks, unless you just have the super basic wire baskets on front. Also many american hybrid/mtb/road commuter type bikes often have mounts for rear racks and nothing up front.

I like the wide platform up top, currently threw my rear panniers on the front and it handles them just fine but as you can see they are poking up awkwardly through the top... Currently making some mounts to hang a bit lower on the rack for panniers, so the top stays clear and accessible. Great for beer runs, though getting much past two dozen bottles can be awkward.