Hi Brit, welcome to the forum
There are people in the UK who have problems with the Mega 1000, see http://dwf.nu/viewtopic.php?t=1230&start=48.
For more information (than you need ) you can read the Mega 1000 related threads in this froum section http://dwf.nu/viewforum.php?f=28.
Display contrast: the positive display has MUCH better contrast than the negative under poor lighting conditions. But the Mega 1000 is one of the best I know amongst negative displays, plus it has a very nice backlight and you will have more opportunity to use it with the negative display
See also http://dwf.nu/viewtopic.php?t=2149&highlight=mega+1000+contrast.