I own Burnley, Wessex, XTC Blue and Harlow. I used all of them through my Helios. I liked the Wessex and the Harlow best for the Helios. The Burnley was cool but the distortion on the amp is killer so no need for the burnley. The wessex was best overall imo but I love the Harlow. The Harlow added wool and made it sustain forever and could nail EJ tones. The Blue, meh. it sounds kinda flat compared to the others with the Helios. still cool but not as good as the others imo.