Erik,
Not too sure about the crashing. I run 14 on a pre-2009 MacBook Pro and it has crashed very rarely.
I also am not having problems with the orthogonal guides. The guide settings can be adjusted here:
Options>Work Environment>Guide Lines
and a few other settings in
Options>Work Environment>Tracker & Coordinate Input
I typically do not hold the shift key since orthogonal lines will automatically appear by default that I can snap to when drawing.
Perhaps with the crashes and the guide problems you should check to see if you have all of the latest hot fixes. One just came out last week.
See this discussion:
http://archicad-talk.graphisoft.com/viewtopic.php?p=181363
HTH