Here are some popular Upwork clone scripts:

# Open-Source Options
1. *FreelanceEngine*: A WordPress plugin that allows you to create a freelance marketplace similar to Upwork.
2. *Project Bidding Script*: An open-source PHP script that enables you to create a project bidding platform.

# Commercial Options
1. *Upwork Clone by PHP Scripts Mall*: A customizable PHP script that offers features like project posting, bidding, and payment gateways.
2. *Freelancer Clone by Clone Scripts*: A scalable and secure script that allows you to create a freelance marketplace with features like user profiles, project management, and payment processing.
3. *TaskRabbit Clone by Appscrip*: A feature-rich script that enables you to create a task-completion platform similar to TaskRabbit.

# Key Features to Consider
1. *User registration and profiles*
2. *Project posting and bidding*
3. *Payment gateways and escrow services*
4. *Project management and tracking*
5. *Review and rating systems*
6. *Admin dashboard and analytics*
7. Customizable and scalable architecture*

Before Choosing a Script
1. Research and compare features
2. Check for scalability and customization options
3. Read reviews and testimonials
4. Evaluate the level of support and documentation
5. Consider the total cost of ownership and maintenance