Is there one antidepressant that's more effective than all the others?

No. For every patient, it can vary tremendously and even ones that work can sometimes not work after being effective initially. So my answer is there is really no one drug that stands above the others in my opinion. It really depends on the patient and what works for them.
Also... Also consider that side effects play an important role in balancing the benefit of an antidepressant. Since side effects vary between individuals, the balance has to be determined case-by-case.