My former sailboat (1993 - 2001) was a Beneteau Oceanis
320. And I have had the opportunity to sail with friends on a 285 too. The fact is I think both of them are a little bit too small for traveling the world. I know a crew (4 people) who cross the atlantic ocean
on an Oceanis
320. They told me how unconfortable it was, how afraid they have been many times, but they are alive, they succeeded. But they never will do it again !
The problem was not the boat in herself, but the fact she (and the crew) was not prepared enough for this kind of "voyage". Well, it depends also of the degree of comfort you need.
IMO, over 35 feet would be more convenient.