They are both outspoken on Twitter for sure but Manoah isn't nearly as annoying for me as Stroman was. Stroman was constantly self promoting and pumping his own tires, and was a giant hypocrite to boot. When criticized on Twitter he would claim that it didn't bother him in the slightest but then proceed to block people for anything and everything. Manoah has confidence bordering on cockiness, but you can see how he is the ultimate team player in how he interacts with his teammates, celebrates their accomplishments etc. Stroman was reported to have feuded with his teammates on more than one occasion. Manoah is respectful with the media whereas Stroman would blow up at a reporter for asking a perfectly reasonable question.
I'm obviously not around these guys personally but Manoah seems confident yet respectful of people in general, whereas Stroman displays a lot of narcissistic traits. Manoah can certainly rub the opposition the wrong way with how he carries himself on the field at times, but I think he's starting to tame that down a bit as he gains more experience and general maturity.