WIX to Shopify Migration

I need to migrate my e-commerce site from WIX to Shopify. The new site should include:
- Product categories
- Customer reviews
- Discount codes

Additionally, I require custom design and branding elements to be integrated.

Ideal skills and experience:
- Proficiency in both WIX and Shopify
- Strong understanding of e-commerce site functionality
- Experience in custom design and branding on Shopify
- Ability to ensure a seamless transition with no downtime

Please provide examples of similar work done.