One problem is that there is scriptural support* for most of the super-culty stuff that they do. It can take a while before you can get to the point where you can really trust your own interpretation of things. They systematically destroy your self-confidence with their constant talk of not leaning upon your own understanding and not putting your trust in the son of earthling man (which includes the GB).
To that point, for a lurking JW, I would point out two things:
First, it's important to remember that we are all individually accountable before god. If something doesn't make sense to you but you go along with it anyway, god isn't going to stand for the "I was just following what I thought was your organization" excuse. Hundreds of thousands of isrealites died following corrupt kings that ostensibly represented Jehovah's organization on earth, what makes you think you'd fare better? This fact alone should be enough to convince any JW (or any christian, for that matter) to investigate any doubts they might have.
Second, I would focus on the ban on seeking outside information. Is this really a scriptural stance, especially if there is any doubt about the correctness of the JW organization? First of all, there are numerous scriptures that encourage one to test things before trusting them, and making the point that truth need not hide from lies (1 John 4:1; Acts 17:11; 1 Thes 5:21; Job 12:11; John 1:5) so, again, is it really scriptural that you should simply trust what you're told by the GB? Is it also scriptural to avoid ALL information from a source outside the JW organization? Why is it not acceptable to examine multiple opinions and settle on the view that you yourself can live with? Going back to the earlier point - we're all individually accountable to god, so it is very important that you're completely comfortable with your beliefs and actions. If something is true, it will defeat any attacks made by it. If something is false, then it will crumble under scrutiny. If the JW organization is true, then there is nothing to fear (your faith will only be strengthened) by examining it's doctrine, if not then you will be personally accountable to god for not examining it.
Applying this latter point to the topic of "apostate" information. For a long time I avoided apostates because it was not worth the time to examine the ravings of a bunch of bitter, angry, vengeful people. The problem is that there's two possible scenarios here - either apostates are bitter and angry and led by satan as is claimed by JWs, or they are justifiably upset and angry at the organization that lied to them and misled them and in many cases took lives and families away from them. How can you tell the difference? The only way to know is by examining both sides of things and examining the organization itself to see if they have indeed lied to you, too. Again, if it's all true, just imagine how your faith will be strengthened once it passes this test. The bible states that tests help you to endure, and that can be applied to your faith as well.
*I mean scriptural support in the sense that scripture is taken out of context and misapplied, but in the minds of a JW (even myself at one time) this is enough to justify the behavior/doctrine of the cult.
