I prefer dot.btc because it's simple. I think bitcoin TLD isn't a good idea because many governments banned bitcoin, so any of TLD about bitcoin will be added to block list
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I'm pretty sure OP's application, if serious, for a bitcoin gTLD would be rejected, if it gets this far, it would, probably, stop here:
3.2.1 Grounds for Objection
Legal Rights Objection – The applied-for gTLD string
infringes the existing legal rights of the objector.
Community Objection – There is substantial opposition to
the gTLD application from a significant portion of the
community to which the gTLD string may be explicitly or
implicitly targeted.
Regarding the Legal Rights Objection : .xxx domain has been introduced in the www even though pornography is illegal in many countries of the world. I don't think bitcoin has been mass opposed by world's governments.There exist certain regulations in some countries and banned in a very few countries.But in most of them the status of bitcoin is yet unknown.