Worse, as good, and incredibly better-all are viable options. Humans are humans.
of course they can, and many times they are even better!! because they choose to be a part of the child's life, they are there because they want to be. being a Dad isn't as simple as donating spe.rm, any man can donate sper.m and make a baby, but not every man can be a Dad! there's a difference between the two, one is just biological, he may be a father but isn't a Dad, a Dad earns the name Dad by his actions and caring. having a biological connection can be very powerful for a parent, but there's no reason a person can't love a child just as much if they aren't their biological parent, there are many biological parents who are terrible and should not be allowed near their children!! but if a person cares and wants to be a parent, and is good to the child, I think they can be a wonderful parent without a biological connection.
Yes! Some biological dads are rapists so a surrogate dad would be better than that! :).
Yes. A "dad" isn't made by the biology of it. There's no real research that I've seen that a person instantly forms an attachment with their biological parent, despite everything. It's being with someone and feeling good with that person that forms attachment. If the surrogate Dad is a good role model, has fun with their kid, and is a good dad all around, there's no reason why they can't be "as good as a biological dad".
They can even be better.