I've seen several launches in December that have done just fine.

I would personally do my best to not land on a December launch...but if it happened, then so be it. I think for the most part, a December launch wouldn't be a real issue. You can always put things on your sales letter that play that angle as well (i.e. talk about them buying themselves a Christmas present etc.).

Alot would also depend on price IMO...if it's a high ticket item, I'd personally be more hesitant to purchase in December, and would bet that there would be a good percentage of others who would be similarly influenced. If the price isn't high though, it wouldn't have any bearing on whether I made the purchase or not. If I'm interested in something, I'm going to be interested whether it's July or December. So long as the price point isn't something that would take justification to myself, I wouldn't be swayed either way.

Sincerely,

Chris