I have a bag from an outlet and think the D4 styling is actually nicer. But it doesn't have as good of a shoulder strap, and think the inside organizer pockets are probably not as good. I think there is a difference in warranty -- but that is unlikely to matter to me. The D4 in the outlets don't have the monogram patch -- but I never monogram any of my bags.

I think the differences are small, though not insignificant.

Remember you can buy at Amazon with th 20% coupon an the difference cuts in two. During Tumi's semi annual 20% sale you may be able to buy at Amazon for 20% off and use the coupon to cut the difference to almost zero. Worked for me last year but YMMV.