I use the Easy Angler ruler because one end of the triangle is blunted already helping accuracy and feeding. It also allows me to use my seam guide to sew the 1/4" seam accurately. Sewing on a diagonal line, for me, is not always so good- some wobbles and such. I also hardly have to trim the HSTs.
Trimming: I love the Bloc loc- it has changed my trimming to being accurate all the time. Make sure the logo goes facing bottom edge to the side the seam is pressed. For example, I press to the dark side and the logo goes upside down towards the dark side. I use it especially when I make HSTs from layer cakes- the sew all around and cut diagonally method. I get perfect matching HSTs when I use the Bloc Loc.