EM is the most forgiving on getting too sweet, but will eventually get there. Stevia can get bitter if you use too much and, is bitter always to some people. Sucralose is very good at making a sickly, syrupy taste quickly and, does have a definite diet sweetener aftertaste to it.
I am one that finds any stevia bitter, and EM is harder to get so, I use sucralose, but I also use the powdered form for my sweet tea, so I'm used to the diet taste of it and, that doesn't bother me.