I thought it was fairly common knowledge about the tests on perfection loop vs other non-slip loop knots - eg. the Non-Slip Mono Loop Knot aka 'Kreh Loop'
w w w dot netknots.com/html/non_slip_loop_knot.html
which tests at near
100% of mono break strength
I too used to think that the perfection loop was very good, with high ratio of break strength compared to the mono being used, but I was corrected, in 2007, on this very board by this:
"JR SPEY 01-18-2007, 04:44 PM
The truth is that there are at least three versions of this knot, not including how many wraps one makes. I've used all three and found all three to be stronger than, for instance, the perfection loop mentioned above, which usually tests out at about 65-75%. I do believe, though, that the version shown in the book referenced above is probably the strongest. However, since I want the break to occur at the tippet-to-fly connection rather than up the leader somewhere (like when I'm hung-up) I'm usually happy with an 85-95% knot, which I think all three versions of the non-slip can achieve when tied correctly."
on the thread
& I have stopped using the perfection loop since.