1. AI Technology: IBM Watson utilizes AI technology to understand and interpret complex data, providing insights for decision-making in various industries, including healthcare and finance. In contrast, QnA Maker is specifically designed for creating simple question-and-answer systems, focusing on providing quick and accurate responses to user queries within a predefined knowledge base.

2. Integration: IBM Watson offers a wide range of integration options, allowing users to incorporate AI capabilities into existing applications and systems seamlessly. On the other hand, QnA Maker is typically integrated with Microsoft Azure services, limiting its flexibility compared to IBM Watson in terms of integration with various platforms and technologies.

3. Training and Customization: IBM Watson provides extensive capabilities for training and customizing AI models based on specific requirements, enabling organizations to develop highly tailored solutions. In contrast, QnA Maker offers limited customization options, as its primary focus is on generating responses from a predefined knowledge base without extensive training capabilities.

4. Natural Language Processing (NLP): IBM Watson is known for its advanced NLP capabilities, allowing it to analyze and understand human language with high accuracy. QnA Maker, while effective for basic question-and-answer scenarios, may not offer the same level of sophistication in NLP compared to IBM Watson.

5. Scalability and Performance: IBM Watson is designed to handle large-scale data processing and analysis, making it suitable for enterprise-level applications with high volumes of information. QnA Maker, while efficient for smaller-scale projects, may face limitations in scalability and performance when dealing with extensive data sets and complex queries.

6. Cost and Pricing: The pricing structure for IBM Watson varies depending on usage and specific features required, potentially making it more expensive for organizations with complex AI needs. In contrast, QnA Maker offers more straightforward pricing models, which may be more cost-effective for companies seeking a basic question-and-answer solution without the need for extensive AI capabilities.

In Summary, IBM Watson offers advanced AI technology, extensive customization options, and scalability, while QnA Maker is more focused on providing simple question-and-answer systems with a user-friendly interface and straightforward pricing.