You can also use the Web console to remove printers from iOS visibility, keeping sensitive or expensive-to-operate printers from being accessed by iOS devices. The password-protected console is also where you install firmware updates, manage the print queue (such as to delete print jobs), enter printer metadata (such as location or friendly name), and set up users (for when you want to restrict printing to specific people). It's a well-designed console that lets you manage your AirPrint environment beyond the default "plug and play, all access" mode.
The xPrintServer's Web console lets you configure printers and user access, as well as add printers not detected by the appliance.
I did find that manually added printers didn't always remain visible on the network. When using a D-Link DIR-655 router, I often had to go to the xPrintServer's console page and refresh the printer to make it visible again. On a Netgear WNDR4500 router, the manually added printers occasionally disappeared but came back after a few attempts to select a printer from the iOS device; I did not have to go to the xPrintServer to reactivate them as I did with the older DIR-655.
Choosing between the Network and Home editions. There are two versions of the xPrintServer: the $150 Network Edition, which supports an unlimited number of network-connected printers, though the company says performance degrades after about a dozen, and the $100 Home Edition, which supports just two network printers but as many as eight USB printers connected directly to the xPrintServer's USB port. (You'll need a USB hub to connect more than one printer to it.)
The value of that USB connection depends on whether you use USB printers and, if so, whether you also have a router that supports such printers, as most consumer-grade ones do today. If you have your printers connected to a router's USB port, that in effect makes them network printers visible to xPrintServer as a network printer -- you don't need to use the Home Edition's USB port.
Choosing between the Network Edition and the Home Edition comes down to the number of printers you have and whether you need a USB port to attach a printer to the network. The $50 price difference is only a small factor.
If you choose the Home Edition, note that Lantronix is serious about its two-network-printers limit. On your iOS device, you'll see all compatible network printers, listed in alphabetical order. But only the first two display as active, and this can be used for printing. If the two network printers you want to use with the Home Edition are not first on the list, access the Web console to hide the printers you don't want to appear. The pair you want will then be made active.