Should I assign or reset a unique_ptr?

Given the common situation where the lifespan of an owned object is linked to its owner, I can use a unique pointer one of 2 ways . .

It can be assigned:

class owner
{
std::unique_ptr<someObject> owned;
public:
owner()
{
owned=std::unique_ptr<someObject>(new someObject());
}
};

The reset method can be utilised:

class owner
{
std::unique_ptr<someObject> owned;
public:
owner()
{
owned.reset(new someObject());
}
};

In the interests of best practice, should I prefer one form over the other?

EDIT: Sorry folks. I over simplified this. The heap allocation occurs in an initialise method and not in the ctor. Therefore, I cannot use initialiser lists.