Loop connection vs. knot

I'm new to this group, and I must admit to being bewildered by the
breadth of topics, and intensity of feelings, expressed. But after
reading the FAQ and lurking awhile, I am starting to enjoy the feel of
the group. Y'all are all right.

I'm fairly new to fly fishing. I converted from spinning gear last year
at the gentle prodding of a friend, who has proven both field guide and
mentor to me, and for whom I am very grateful. I am *really* enjoying
fly fishing for the challenges it presents, the intimacy of being right
in the stream, in the action, and the exhilaration of hooking and
fighting a fish on a fly. It's awesome fun!

My Question: Are loop connectors at the end of your fly line an
advantage? They sure make it easy to change leaders, but do they
provide sufficient transfer of energy from line to leader? Is it
"better" to use a nail knot? Or does it matter?

Philosophize at will.

Tim