At the office, I let UPD search for all available network printers. The results differed from what Mobile Express found -- instead of a list of IP addresses, UPD offers a list of model name and numbers. Interestingly, neither found the JetDirect-attached LaserJet 4000, while Mobile Express picked up on a LaserJet 1200 that UPD missed. I knew the IP address for the LaserJet 4000's JetDirect adapter, so I used the IP address search capability to map to the device. That worked.
UPD doesn't gray out unavailable printers, as Mobile Express does, but you can click the Check Status button for a printer before sending a job.
When you print using UPD for the first time, a dialog box comes up. Click on the "settings" hot link and a third dialog box appears with radio buttons telling the driver to always prompt you for the printer (default), to prompt you only the first time an application prints or to prompt you only when the last known printer is unavailable. Since I primarily print to one printer at each location, I chose the latter to get as close to one-click printing as possible.
UPD doesn't support direct-attached printers -- obviously, it wasn't written with consumers in mind -- but does recognize printers locally attached to other computers on a network that have been configured in Windows to be shared peer-to-peer across the LAN. In my home office, where I have other computers on the network, I was able to use UPD to print to my HP LaserJet 1018 by attaching it to a PC and configuring it as a shared printer.
But in my satellite office, I was unable to use UPD with the direct-attached HP LaserJet 1200. To use UPD with it, I would either have to attach it to another PC and share it to the network or buy an external print server for the LaserJet -- at a cost of $65 to $99, depending on the model. Since I don't need to share that printer with anyone else, the only benefit would be the little extra convenience of easily accessing other HP printers -- probably not worth the investment.
One advantage of using the HP UPD driver is that it offers more settings for the HP printers it manages, including diagnostic codes and alerts, than Mobile Express. Features available through UPD include scaling, an economy printing mode that saves ink and a wider variety of finishing options. During testing, UPD warned me that the 4000 black cartridge was low -- something that Mobile Express couldn't tell me.
As with Mobile Express, UPD couldn't discover printers in my home office when connected over the VPN in the Framingham office. However, it did detect online the status of and print to devices that it had previously discovered while I was in that office I had no trouble printing to those printers over the VPN.