I am thinking of splashing out on a Garmin for road and mtb duties as i am moving to the usa and won't have a clue of my way around. From what i can tell i am going to need different maps for where i am going to live as it's right on the border of Kansas and Colorado. These maps only come on DVD, so how do the maps go onto the device? Is it a pain in the ass to change maps over? Also, are the devices up to much?

The devices are great, although for mapping and speed of refresh they don't compare with a dedicated satnav or iPhone in my experience. What they are is a very comprehensive, robust bike computer that also stops you getting lost. From memory it's easy to upload maps via a pc and there is a micro sd slot, so plenty of storage space.

Have a look at openmtb maps. You should be able to find some free maps to upload

+1 for openmtb maps. They tend to be a bit detailed which can slow the device down but the guy has done a nice job of styling the trails to try and show what they are.

To answer your question on how to get them into your device, you just plug the Garmin in a PC and it appears as a USB drive. You can then download from openmtb maps a file called gmapsup.img specific to your region and then copy that up to the device. Just one at a time though.

If you want more than one then you need to merge two files together which is a little more complicated… Or you can my a microSD card and stick that in to the 705 to give you a second map but I've never had good luck with that

Cheers, that's reassuring! Oh, and i should have asked are they mac compatible?

My 605 appears as two removable disks on my mac, one for the internal memory and one for the SD card; I assume the 705 does the same.