TLC vs. Almost new
I don''t think that this is a question that has one single right answer. Ignoring the financial aspects which generally favor buying used by a long shot, there is the time issue. Fitting out a new boat can require a lot more time and effort than buying a used boat that was well set up and is in good condition. To some extent, you need to pick every single of non-standard gear and manage getting it installed properly. Replacing my boat''s electronics after the lightning strike has proven to be an extremely time consuming seven week process even with a boat yard doing most of the work. That is but one small piece of fitting out a new boat. Back in the 1970''s I had a job commissioning boats for a company that sold new boats. The boats were very simple back then but commissioning even these simplier boats was a huge job, perhaps a larger job than bringing back a boat that was in moderately good condition.
The other issue that comes into play is one of taste. For some there just is not a boat that is in production that is as right for them as some older model. For others there is no older model that suits them as perfectly as some specific newer design.
I typically feel that only very experienced, very wealthy sailors, with lots of time on their hands and very specific needs that cannot be met in the used boat market should buy a new boat. For the rest of us, buying used is a pretty compelling case.