I thought I'd post this and see if others have had the same experience. The most common braids I have used are the TF XP and then the Varivas GT. I have found knots with these very easy to tie.
I, however, decided there was no harm in trying some others so I got some Fins braid in the 130lb. Now as some of you may be aware, Fins claim that their braid is far more abrasion resistant and that knots have far less slippage.
Well, that may well be the case but that lack of slippage sure makes it bloody hard to tie bimimi doubles. I've been playing around with it and I have found that it is really hard spreading the loop to make the braid come back upon itself when you tie the double. Because I like a very short loop section, I tie it using a finger bimimi (thanks Duncan). I find that a fifty turn bimimi is okay but a 70 turn bimimi is tough.
It can be done but it doesn't roll anywhere near as smoothly as the TF XP or Varivas. I don't know whether it is because the line isn't as round or what it is but I can well believe their claim of less slippage. In a lot of ways, I find it is a bit like the old spiderwire which was one of the first braids on our local market. That was a mongrel of a thing to tie knots with.