This was the recommended app to update shipping dimensions for ShipperHQ. I can't image how anyone could use the export for updating a large amount of products. For my needs the export is almost unusable.
With this app the metafield values export in rows instead of columns. My 2600 products exported into 35000 rows on the export. Other apps I found export the same data into 7500 rows.
After a lot of searching I found a better app that exports the data perfectly. It's called Excelify. Excelify is more expensive but it's the only app that exported product and variant data together with metafields in columns.
Some troubleshooting advice:
To prevent a failed import, in both Excel and Google Sheets, convert the ID column format to "Custom Number 0". Both Excel and Sheets have a bad habit of condensing the long ID number which results in a failed import.
Be sure to import and export data in UTF-8 format. This seems to be the standard for metafield apps.
Unless you are a developer, this app won't help you. Set up is easy. Creating metafields is easy, but then doing anything with them is where this app falls down. Shopify doesn't give you any access to the fields (in product export for example) so you have to use the export utility in the app. The problem is that creates a line per product per metavalue, which unless you are going to throw the results into a SQL database, is beyond useless.
I can see the point of the app for some people, but it didn't solve our problem for creating the technical details as fields on products as a simple grid layout for our price list.