I would have nothing against a single dad at all...If he is the right man for me and i am the right woman for him (and this is the precondition) I would welcome his children as long as he and they can really make space for me, i.e. accept me as an equal member of the familiy....
Not as a rule, but I often find single dads more interesting than single men with no obligations -- probably because I think it's more likely they have more sense of responsibility (though i may be wrong?)...+ I like children...