Yes, Vantage has a built in .csv importing tool which you can see from the Vantage admin demo site here. The theme comes with an example .csv file which includes the specific fields which can be imported by default, and these are the basic listing details as you would see on a Vantage demo site listing. It is possible to customize the importer though, and allow more fields as described in this tutorial. Thanks.
We have some documentation available with regards to uploading very large files which you can read here. And another point to consider when uploading a large amount of listings is related to Google Maps. This post explains more about it. Hope this information helps :)