Just hang in there and do some more research and mulling over of the various papers on this site - there are some really fine insights here (FAQ, Rebuttals, etc.):
http://www.fairtax.org/index.html
I've read most of the website over the years and I re-read portions constantly. Plus there are new documents added all the time, so it is good to run through it periodically. I also like to go through the "News" page and read what pundits are saying -- sending letters to the editor when I see something mis-represented.
About the Prebate: Although I am happy that no group of voters would have an incentive to increase the rate, the basic premise of the Prebate is still weak.
There is no getting away from the fact that it is an added cost and increases the FairTax rate necessary to raise the revenue required.
I guess it comes down to a question of "need". Do you have a good argument why it is needed ? One that doesn't rest on the merits of creating a "progressive" tax system ?
BTW, the deadline for submitting comments to the Tax Reform Panel on the proposals submitted so far expires on June 10th. The comments submitted so far are overwhelmingly in support of the FairTax compared to any other plan. Of course this is all about awareness, and not really a representative sample of the man on the street. Sadly, most people do not want to think about the taxes they pay. Taxes are a lot like death that way.