What looks amazing from the outside might be quite stressful from the inside, and vice-versa. I think we aren't able to predict a relationship before we experience it because each person adapts to the other, and the result is undetermined before the process starts. A person becomes changed in a relation, we can't predict even how we are going to be, let alone the significant other. That has been my experience - I'm rather pessimistic at dating services being able to match people up. It's more of a game of chance.