Well, since Guthix is not a real god (no WAY!!), I will go by the advantages Guthix gives. His book is definitely the worst (+ 5 attk, +5 def), his magic spell is air strike compared to sarodomin strike, but one good thing is that he supports the void knights. This can be bad, too, in that he supports the void knights and all the pest-controlled high level immature kids you see. Sarodomin > Zamorak > Guthix