Open-source GUI development tools and proprietary GUI development tools differ in several ways:

Open-source GUI development tools:

1. Free to use, modify, and distribute
2. Community-driven development and support
3. Transparent source code
4. Customizable and extensible
5. Often cross-platform compatible
6. Examples: GTK+, Qt, wxWidgets

Proprietary GUI development tools:

1. Commercially licensed, may require fees
2. Developed and supported by a single company
3. Closed source code, trade secrets
4. Limited customization options
5. May be platform-specific
6. Examples: Microsoft Visual Studio, Apple Xcode

Additional differences:

Open-source:

- Collaborative development
- Faster bug fixing and feature additions
- Wider platform support
- No vendor lock-in

Proprietary:

- Professional support and documentation
- Integration with other proprietary tools
- Potential for better performance and optimization
- Vendor-supported training and resources

Choose open-source for:

- Community-driven projects
- Cross-platform development
- Customization and flexibility

Choose proprietary for:

- Commercial projects with specific requirements
- Integration with existing proprietary tools
- Professional support and training

Ultimately, the choice depends on project needs, resources, and goals.