Whilst deciding which pedal to purchase I seem to have ended up owning both! Not a problem though as they are both keepers.  The Seamoon has a more specialist remit but if you like it, and I do, there's no substitute. The SGFX is more what you would expect from a filter pedal with some classic funk settings which has found a permanent spot on my pedal board. Seamoon Funk Machine; This basically has two sounds, the classic Brecker Brothers 'sponge' envelope filter and a 'sub-dub' d