I used this migration to switch from Big Commerce to Shopify and worked perfect. Well worth the $128.

As an official Shopify Expert, I handle store migrations all the time. I've tried the other migration services out there ... and C2C is definitely the best option. There's certainly a learning curve (with regards to picking the right migration options C2C offers, as well as installing the bridge file for Magento stores) but their support responds fast and is helpful. This app has literally saved me hundreds of hours over the past 2 years!

POOR order migration service
While it was importing, It was stopped at certain period, and requested to run again. they did send all customer and text message notification turned ON
and all the customers got tons of email and order confirmation text messages....some customers were received text messages for few hours

This was DISASTER !!!!

Great time saver from Wix to Shopify. Don't expect it to be a perfect 'clone' you will have to add a theme and tweak a few bits in Shopify yourself after migration. Be the new cart will be better. It's saves so much time and gets you up and running quickly. I had some fantastic on-line help from chat support also. It's not scary but you are not alone ;-)

We have used Cart2Cart to Migrate from Magento to Shopify. It has been a good process and their tech engineers have solved all our custom reguests in the process of the migration :o)

good support team for responding, extension easy to use to export a magento website i have a 10 000 products, 5000 customers...

I tried it before, It works very good. It can import images, customer database to shopify from oscommerce.

I have to update my review, this app transferred the products over with the pictures and descriptions. But seems to have caused a lot of issues. Redirects are not proper, titles/descriptions now have utf decoding issues. Pay for the basic features and plan on doing all of the labor intensive stuff by hand.

Used this to migrate from Volusion to Shopify. It did a good job of migrating all of my products. Migrating previous orders and customers was a little less successful. When I contacted customer service, I would have had to give them login info and passwords for both my target and source stores. Which I didn't feel comfortable doing. I would have rather them looked at my CSV files.
If you have a lot of products and photos it is most likely worth the price.

Migrating nearly 30k entities from Big Commerce to Shopify is pretty daunting but this certainly took most of the pain out of it. It's not cheap by the time you've added on a lot of the extras (301's, categories > auto collections etc) but it is much more cost effective than doing it manually as dealing with CSVs for this amount of products/order/customers would take days.

If using for the first time i'd definitely recommend getting insurance just in case it doesn't work out as intended. Also temporarily disable notifications in Shopify if you're migrating orders otherwise you'll get a lot of emails!