Best practice for importing participants with additional attributes?

Hello.

I want to import a set of users from a .csv file with additional attributes. It appears that there are two easy ways to accomplish this.

1) I can importing them directly to the central participant database and then share some or all of them with a survey.

2) I can initialize a token table and then import the participants along with the additional attributes directly into the token table. If I want, I can add these participants along with the additional attributes to the central participant database.

So, what are the relative advantages and disadvantages of these two approaches? Is there a 'best' practice?

Thanks!

Rick

I tried to include the additional attribute in token but it confuse me.

In first time I import a short list (test) from csv into central participants and add them into survey, initiate token, start survey, I can export result to csv with additional attribute.

In second time I decide run the survey, import 500 list into central participants, but there is problem in mapping attribute I have to delete all existing attribute and create it when import, but this time there is no additional attribute in export csv result.