Before I bought it I saw it demo-ed with ozmaps as an underlay. I have always been meaning to get the oz maps topo mini SD but haven't yet.

The original garmin ram mount in my humble opinion is a piece of manure that should be tossed into spare parts bin asap. If you go the zumo route buy a Touratech mount they seem to be the only thing that stops the interface pins from permanently stuffing up every 5000km.

The other one I use a fair bit but it isn't water proof is VMS 700 gps in the fire truck which is a great bit of kit. Huge screen. And it gets shaken to extremes in the big red truck so I recon it would last on a bike. I haven't seen any sort of bike mount for these.

The way things are going with i-pads and such, the next one I will buy is something like a i-pad with a usb dongle. Some of the mapping GPS gear you can buy for a i-pad is pretty good. And a really big screen is great especially if your like me (short sighted and slow retinal response) and it takes a bit to re focus from the road ahead to a display...