As an aside to these answers; currently running 2 local (WAMP) installs. My server is down and not sure where I will be going with it.
Tabbed edit screens – The difference in loading is so small that I hardly noticed. I haven’t experienced any unusually high CPU useage as I have read about in the support postings. It is not a major issue for me but I prefer the current setup. It allows me to make follow on actions without switching back to another tab to access the navigation items.
Resource menu pages – I also generally don’t initially use the selections but those users with very large “reports” might prefer the current setup. Either option works for me.