wouldnt touch xxx
I cant see any positive reason for anyone to want a xxx domain.
There are only two practical reasons why there are different TLDs
1. to resolve naming conflicts and allow different people to have the same domain which increasingly is a moot point considering the number of companies that succeed in laying claim to a domain name across all TLDs.
2 to permit a company to different geographically targeted sites.
As .xxx is a non geographic TLD and also potentially pron to censorship. Porn site operators arnt going to drop their .com domains and most of the registrations of xxx domains will be merely to secure their name accross both TLDs.
While likely some countries will no doubt try and block the xxx TLD there is also a risk even to those registered on xxx merely to secure the name used on their .com site censorious bodies may use the xxx TLD as a 'confessions list and block at IP level
At 7 times more and the risks associated with it I would just let it wither