While personal experience is insufficient in convincing people, it is not completely insufficient.

From the evaluating Christianity website:

http://evaluatingchristianity.wordpress.com/the-summary-case-for-atheism/arg1long/

A. Subjective Experiences Are Hearsay

As a threshold matter, when one person claims to have had a direct, revelatory experience of God, that claim is direct evidence only for that person. From my perspective, it is hearsay. I can’t evaluate your experience; all I can do is evaluate the fact that you’ve claimed to have such an experience.

Now, I have no doubt that religious believers who claim to have experienced God in some subjective or visionary way are, on the whole, generally sincere about those claims. But those claims are, of course, not restricted to Christians. Jews, Muslims, Buddhists, Hindus – people of every religion claim such subjective experiences, and they can’t all be true.

The key part here of course is 'direct evidence only for that person,' logically of course, it is quite poor in regards of convincing others, however this does not discount the personal experience as genuine or true, it could in fact be true, it is also interesting that he uses the word 'hearsay' since hearsay is admissible in court under certain standards.

http://criminal.findlaw.com/crimes/more-criminal-topics/evidence-witnesses/hearsay-evidence.html

B. Subjective Experiences Can’t All Be True
Because all sorts of believers have the same sorts of experiences — and they can’t all be true — we resort to methodological naturalism (see part 4) to evaluate these sorts of claims.

Critically, even Christians themselves use these techniques to evaluate claims of personal subjective experience when raised by non-Christians. One particularly compelling counterexample comes from Mormons, who believe that seekers should pray about the Book of Mormon to see if they receive a “burning in the bosom” – a subjective verification – that it is true. Here’s how an evangelical Christian apologist evaluates that argument:

What we must understand is that Latter-day Saints (LDS) believe these things for the same reason that people everywhere believe the things they do: they want to believe them. … This should come as no surprise to evangelicals who have read the Apostle Paul’s revelation of the roots of human idolatry in the first chapter of Romans. Fallen humans have affections and inclinations that they then prop up with beliefs, convincing themselves that their systems are true.

Another evangelical is a bit more direct:

Remember also that Paul never asked any potential converts to pray about his message. What he taught was found in the Scriptures and they could verify it and join the group of wise people, if they would repent and submissively place their faith in Jesus Christ to follow him. See Acts 17:11,12 cf. Acts 20:21; etc. … Yes, the devil can duplicate peace. That is what he does in transcendental meditation (TM) and also in Catholicism after one receives the Eucharist. The devil uses these and other experiences to deceive.

This is misleading and shows a fundamental misunderstanding of Christianity, since it specifically states that other religions have their own set of signs and personal experiences. In Genesis 7:11-13 it shows the Egyptians turning the sticks into a snake, just as Moses and Aron had.

¹¹ But Pharaoh also called the wise men and the sorcerers; so the magicians of Egypt, they also did in like manner with their enchantments. ¹² For every man threw down his rod, and they became serpents. But Aaron’s rod swallowed up their rods. ¹³ And Pharaoh’s heart grew hard, and he did not heed them, as the LORD had said.

The point here of course is that personal experience found in different religious groups can be true.

In the most extreme cases, we think people who hear divine voices are suffering from paranoid delusions. Consider the sad case of Andrea Yates, who (apparently) sincerely believed that she heard the voice of God commanding her to drown her five children. On face, her case isn’t any different from what Abraham claimed to have heard directly from God in Genesis 22:1-10. Why, then, does virtually every Christian have no difficulty concluding that Ms. Yates was insane?

Actually I don't concede Yates was insane(there goes your 'virtually every Christian assertion) since I am not qualified to make that decision, of course I concede that Yates did not hear the voice of God in any way similar to Abraham since God stopped Abraham from killing his son, something the author seems to have omitted.

¹¹ But the Angel of the LORD called to him from heaven and said, “Abraham, Abraham!”
So he said, “Here I am.”
¹² And He said, “Do not lay your hand on the lad, or do anything to him; for now I know that you fear God, since you have not withheld your son, your only son, from Me.”

I mean really? honestly? it was just 2 lines down(this is called quote mining). God stopped Abraham from killing his son so if the authors assertion that "On face her assertion isn't any different than Abraham," had any truth to it, God would've told her to stop.

I submit that whatever our “worldview” — in day to day life, we are called upon to evaluate claims like this from a variety of religious, spiritual, and other sources. Uniformly, we reject these sorts of experiences, standing alone, as being sufficient justification for the truths of the beliefs asserted in those experiences.

For all of these reasons, I conclude that this first set of arguments is insufficient to warrant belief in God

The conclusion should be changed to 'this first set of arguments is insufficient to warrant a convincing argument to believe God exists.' It is important to note the purposes of a personal experience, if someone asks why I believe Christianity is true I sometimes respond with "My prayers are usually answered, I have felt Gods presence etc," the atheist replies "well those are personal experiences, how do I know they actually happened," to which I reply, "You don't know they happened, but you asked why I believe Christianity is true and I gave you an answer," it is interesting how some atheists I have encountered don't know the difference between simply stating information and an argument to convince them the information is valid from their worldview, there is nothing wrong with stating you have personally experienced God, both atheists and theists need to realize that personal experiences aren't convincing arguments.