My hubby uses stevia for his coffee. he was diagnosed diabetic about 3 years ago & that was one of the things we changed right away as stevia dosent spike your suger levels (he used to use sugar & drinks a fair bit of coffee) Hes no longer diabetic. hasent been for over 2 years (& yeah the drs are poed all to bits over that.. not possible, lab results must be wrong blah blah blah)
Anyways as a sub for sugar I would definatly recomend the stevia.
Xylitol we havent used & ive mostly heard "good" about it compared to say sugar but its toxic to dogs so if you were to use it & you have dogs then make sure its safely out of reach