I believe that the BIG difference between the II and the II PlUS is that the plus comes standard with a 2GB Memory card and is PRELOADED with the entire USA and Canada.
The standard Nav II only had 512Mb and wasn't pre-loaded. The 2GB of the Nav II PLus is a good deal.
I just purchased one for my GT and it looks really good. I powered it on and was ready to go right out of the box. No map downloading needed. Really nice!
I like the BMW unit. The extra buttons are cool. Plus all the BMW dealers are on the maps. My 2004 GT was already wired for the unit so I don't even have to pull the bodywork off to install. It came with the mounting bracket for my GT and all the cables that I need for the bike, the car or with an AC adapter in the house. EVen came with the USB cable so I could download all my waypoints.
There is a dealer selling new ones on Ebay for $999. That's where I got mine.
A summary of the key features of the new Navigator II Plus:
comes as standard with a 2 GB compact flash memory card (compared to 512 MB on the Navigator II and 128 MB on the original unit)
the Navigator II Plus can be used immediately (plug and play)
the unique mounting cradle is designed for operation with gloved fingers. The unit can also be removed quickly when leaving your parked machine but can also be secured safely with a special screwdriver
Bluetooth technology available with BMW's System 5 helmet will enable integrated wireless communication of voice directions to the rider (currently in development)
an audio socket also allows voice directions (in a choice of 12 European languages)
navigation includes turn-by-turn route finding with a choice of shortest time, shortest distance or linear distance options
the fast processing speed allows for virtually instant, automatic route calculation whenever the route is left
four trip computers show current, average and maximum speed, elapsed time, time stopped and total time
routes and waypoints can be planned (and stored) on the pc or on the unit and then shared via email with other users
a compass function allows for off-road navigation, or navigation in areas where mapping doesn't exist or is unreliable
the unit is completely portable. It can be used in any vehicle (it comes with a power socket adaptor) or by walkers or cyclists if used with the optional battery pack