Currently, the VX-1210 may the best option for commercially available "No assembly required" manpack operation. It is difficult sometimes to find a dealer who is knowledgeable. Most will sell to you at 20% of list, and some can beat that price on the radio by selling you their demo unit.
The VX12 Yahoo Groupis the best source of information on this radio.
The VX-1210 must be programmed using a hardware interface and Veryex software. Many of the difficulties hams have had with operating the VX-1210 stem from improper programming. The programming loads frequencies, settings, and button configuration. If set incorrectly the radio does not perform well, functions may not be accessible, and can be tedious to change frequencies.
A recommended radio configuration & programming file is available in the VX12 Yahoo Group, and it should be used as the starting point for customization. The button configuration it provides is optimized for amateur usage, and allows all functions to be used.
The software can be tedious to get working with USB serial ports. The trick is to identify the port number and make sure it's set correctly. You may have to delete the device and re-add it, or manually set it to a lower Comm port number. It also helps to use the same usb port for your serial device, as that can change the comm port number.
Bonnie KQ6XA has documented several good mods on the VX12 Yahoo Group. I have a couple in progress which will be posted both on this page and their when complete.