One of my networks is named Fubar (and with good reason at the time but it's been stable for a long time now.)
I upgraded from 6.6.3 easily. There are many nuances in upgrades: what the starting point is, P2P vs server, server memory, locations of memory. All of them can introduce issues, I've noted in the past.
For me, the upgrade was smooth, faster than I've done in a long time. I did test it out on a trial computer. This occurred shortly after merging of my 2 databases.
I can't speak for you, but for me, it was not an issue at all to upgrade. It did make a number of things better.
A related question is how easy was it to get help (and by what route) and were they helpful?
