I have no connection to DHL or Airborne. I'm not particularly a fan of the service they provide because of the somewhat unpredictable nature of their overnight deliveries. But I can't say I really see a difference between the courtesy or professionalism of the drivers I deal with on the customer side. I don't know how the companies compare internally, within the hubs, as my experience is limited to UPS in that regard.
As for the cash from operations compared to the cash UPS has on hand, I see the difference being how the two companies have to answer for their investments. DHL is in growth mode, and is using cash from operations to rapidly grow the business.
UPS has the Berkshire Hathaway problem. It is difficult to have a meaningful effect on the bottom line given its size. It isn't hunting rabbits, it is hunting elephants. I don't think UPS really can grow its ground business much. With FedEx and DHL taking business away, UPS gains more or less keep it even.
In the next decade or two I expect the small parcel business to be less the mainstay of UPS and more of a package of supply chain services offered to clients. This is probably a good thing, making UPS less sensitive to the U.S. and other economies. Indeed, a stronger presence in supply chain services will probably mean UPS is stronger and performing better during bad times.
That's a big reason why I left UPS. The game isn't in parcels going forward. I was in a hub, and had little chance of getting out and into Logistics like I wanted. UPS's small package business will probably go through some trying times in 4-5 years, maybe a bit sooner. It will be a company less labor dependent. It will be interesting to see how it plays out. I still have all of my UPS stock, but I must admit I worry about labor strife if DHL and FedEx accelerate the decline in small package business.