In general the help in 2010 is quite good. If you hover over a command icon, Revit will give you some good help tips and by pressing F1 you will get full help on that specific command. However this method of help does not work when you are in the middle of a command on tools in the options bar. In Revit 2009 you could just use the “What’s this?” tool to get good help on items in the options bar.
The “What’s this?” icon is not on the 2010 dashboard, however if you use the old short cut, “Shift + F1” it works and you can get help on commands in the options bar.
This is another UI shortfall with 2010. How many beginners are going to know the old shortcut.