I have leopard and new NUDC and I am having some issues with 5.3.1 especially links from calendar items (calls, appt's) to contacts having errors...
Not sure if the beta will help this but I can't download it... I try this link
ftp://ftp.nowsoftware.com/pub/software/support/nudcm532b3.dmg
but everytime I get error "failed to open page".. I've tried safari and firefox
thanks
Bob