Mind Lab Pro®
I've had a real difficult time with this app and it's corresponding cli tool.
The app itself is easy to install and simple, +1 for the fact it also has a 'Delete' option to undo everything you've done file by file if it all goes wrong.
The only issue with it is the poor import rate on customers and in particular the dreaded 'Phone is invalid' error. Literally 70%+ of our customer imports failing on their phone number not being in E.164 format. The developers of the cli tool didn't think to use the country code in Magento to convert phone numbers from Magento into an E.164 format, so the import rejects all these otherwise perfectly valid phone numbers.
If you are a Magento dev who needs to do this then this answer -> https://stackoverflow.com/questions/41774883/formating-phone-number-according-to-the-e164-format in combination with this library -> https://github.com/giggsey/libphonenumber-for-php is what you'll have to go through to get these phone numbers in the correct format to allow customers to import. Also note that it's a bit of a nightmare dealing with linebreaks in the address when you are trying to fix this, I also used this library (https://github.com/parsecsv/parsecsv-for-php), my working code to fix this is in the gist -> https://gist.github.com/mcnabsystems/83728516bf6e7c3bebc107acdd9e54df
For large Magento installs with hundreds of thousands of customers and orders the cli tool to export data to csv is dog slow as they have used Magento's SOAP API, and there's no way to speed it up;
You are looking at weeks here for data exports on stores with 100K+ orders and customers, not hours. Maybe they should have taken a leaf out of the Excelify App author's technique and used the database tables directly rather than Magento models.
Additional problems I've encountered;
1. I struggled to get the ruby gem for the Transporter cli tool installed and working on our original Magento dev server running PHP 5.6. Eventually got it working by creating a new Ubuntu 18.04 instance on a Digital Ocean droplet and upgrading the dev Magento site to 1.9.4.
2. Docs on cli tool very light, few example of how to use commands and no examples of using any options. For example even though the cli tool exported data for customers with the website_id in the data, I was not able to run the conversion command to include website id via the config. According to the docs there should be a way of doing this but I couldn't get it to work. It is an important omission because you'll need to do it if you are migrating a Magento multistore to a number of separate Shopify Plus instances each with a different currency.
3. As mentioned above, it fails to validate or modify crucial data so that Shopify will be able to import it.
Sorry Shopify - I love your platform but I can't rate this tool at all. Magento to Shopify Plus migrations are going to be big business for you and this app is a selling point for those migrating. It needs to be improved.
Overall score here, 2 out of 5 for the CLI tool and 3 out of five for the App, overall a bit generous on 3 out of 5.