I have no problem with running under Windows 8 64 bit.
I did have to purchase
a new GlobalSat BU-353S4 GPS
on Ebay as I had mislaid the previous one. It is a good investment as it is much faster to connect, can find more satellites and is much more sensitive. Was $50 Australian on Ebay. Works well on both my Win 8 desktop
and "XP" lightweight Sony laptop
which is too old to be upgraded.
I have also installed the start button with the free Classic Shell.
As Win 8 was an upgrade I have the best of both worlds, one mouse move and click and it runs as a Win 7 desktop or as a Win 8 desktop.
My next challenge will be if I get an Android tablet, but it seems from reading that the earlier problems have now been resolved.
Mind you I have a Simrad
chart plotter mounted in the cockpit
table between the wheels and only use OpenCPN
as back up and for planning with CM93 Charts
(Jan 2011) which interestingly seem more up to date in the area I usually sail than those on the new Chart Plotter (late 2012) and are easier to update.