Bimini Twist is the Winner!
You are not going to tie a Bimini Twist for your standard nymph setup. However, if you are going Stripper or Redfish fishing you may want to consider it. The other knots shown are used all the time. Rio test the knots for tensile strength and the Perfection Loop was a big surprise as to how strong it is.
Three fly fishing loop knots; how to tie them and how to join them from RIO Products on Vimeo.
Bimini Twist Can Be Used Here: Dolphins Make There Own Loops
Strength of a knot can be put to the test....