[rules-users] What's more efficient?

I have a question regarding the performance of pattern matching. Is it more performant to use join nodes, or to use a from? For example. With joins I could write a rule like rule "Foo Join" when Foo($bar : bar != null) Bar(this == $bar) then ... end rule "Foo From" when $foo :Foo() Bar () from $foo.bar then ... end thanks