Uber-Style Multi-Platform App Development

I'm looking to develop an Uber-style app that functions on both iOS and Android platforms. The app's primary purpose will either be ride-hailing, delivery service, or both, to be confirmed.

Key Features Required:
- Real-time GPS tracking
- In-app payments
- User ratings and reviews

Ideal Skills and Experience:
- Extensive experience in developing mobile applications for both iOS and Android
- Strong background in implementing real-time GPS tracking
- Secure in-app payment integration expertise
- User-friendly interface design
- Proven experience with ratings and reviews systems

Please include portfolios and relevant experience in your bids.