The reason that people break in engines on conventional oil is that they are generally going to change it early because an engine has plenty of dirt in it from assembly, and sheds lots of metals during break-in. No use throwing away expensive synthetic oil like that. Some people (not me)feel comfortable that the oil filter is going to catch all the crud, so they leave the oil in longer. Honda sometimes uses a special oil as a factory fill and recommends that people leave it in for several thousand miles. Other companies don't. Then it's your choice. Synthetic oil isn't going to stop the engine from breaking in or anything. Mostly it just flows better in the cold, and lasts longer.
The debate about shorter OCIs with conventional oil or longer OCIs with synthetic oil will never be settled. Consider these two things when making your own decision:
1) Synthetic oil does not break down as quickly as conventional oil, but it does pick up condensation, fuel dilution, and dirt just as fast. The only way to get these out is to drain the oil.
2) As specifications improve, the difference between conventional oil and synthetic oil keeps getting smaller.
