I don't know if you know but the Tumi models with numbers ending with D4 are what they call Generation 4.4. The newer ones have model numbers ending with DH. The primary difference between the two (as I see it) is the weight. The newer DH mdoels weight much less. In case of belreifcases they are as much as 30% lighter. (trust me I actual weigh bags-as you can see my earlier posts). So, the lighter weight comes from thinner inside fabric, less leather on the handles and shoulder straps, and overall lighter materials pretty much everywhere except the outer fabric. If I were you I'd save some money and go to a tumi outlet and purchase a gen 4 bag. My gen 4 briefcase is in it's 12th year.