In your opinion, what is the single most advantageous factor in believing in God?  ?

As an agnostic atheist, I would say probably the built in sense of community, shared values, and support network which comes with belonging to a specific faith.

If you're an actual believer who walks the walk instead of just talking the talk, you'll regularly spend time with other people with whom you likely share a great deal in common, which makes it easy for you to find friends.  Other members of your faith will also often come together to support you in your hour of need.

If you lose your job and are having a hard time feeding your children, you may suddenly find that others in your congregation "made too much."  They "had some left over," and don't you feel at all guilty about it; it's not charity "because if you don't eat it, it's just going to go to waste, anyway."

Need clothes?  They've got hand-me-downs, and it's not charity.  You're doing them a favor, letting them get it out of the house.  Saves them from having to make a trip down to Goodwill

And of course, because they've done this for you, it tends to have a positive impact on your sense of well-being.  It takes a lot of stress off you, and negative stress tends to be one of the biggest things that can contribute to poor self-care, poor physical health, negative outcomes for any healthcare  problems, etc.

That, of course, is contingent upon you belonging to a faith that's healthy to begin with.  There are always counterproductive churches and sects which might force you into doing very maladaptive things, such as refusing to get proper medical treatment for family members, or telling women they have to submit to their husbands beating and raping them.  Those are bad congregations, and we know the best thing you can do if you're in one is get out and get help to recover from the damage they almost inevitably did to you.

Those aside, though, when it comes to "normal" churches, there tend to be a bevy of benefits you get from belonging to a faith.  That in no way speaks to the veracity of the faith itself, but the positive effects of being part of a faith-based community are well documented.

Plus, if what you believe brings you comfort, and a sense of purpose and fulfillment, I'd say that's a pretty good perk. 

Even if it's not true, and your mind just shuts down when you die, let's face it, all the faith really has to do is get you to the grave, and as long as you die feeling an optimistic hope about your future in the afterlife, rather than abject terror at dying and losing everything, then you got some good out of the deal.  Even if you didn't get what the religion actually promised, you got something which, for all practical intents and purposes, was just as good.

So yeah, I'd say all that's pretty good.

My belief in God helps me be a better person. I am awed at how he designed humans and this fabulous planet that he designed for our well being and pleasure. I am so glad he decided to create!

You will become wise.

Knowing your Creator.  It means everlasting life to do so, and He is Love.  John 17:3; 1 John 4:8

An effort to have a holistic view of Consciousness which permeates existence.  

Knowing the truth, and being able to enjoy the benefits of the truth.

A security blanket

Personal comfort

Profession of faith and sincere repentance towards God The All Creator.

In a word, community.

The opportunity to glorify God!