Speaking as an atheist I would still quite happily join the Cult Of Baltar. Plenty of really fit gals with guns, and Baltar himself is such an adorable little weasel. And monotheism is liek a totally radical viewpoint in the BSG universe, dude.
I haven't read up on Mercerism to any great extent, but it sounds bloody awful, with all that uphill grind all the time(I also find DADoES a bit of grind too, so I've never read it properly)
Gun toting girls with Gaius Baltar as their Personal Jesus Vs. Mercerism? No contest!
And my answer is relevant because BSG has got skin-jobs too!