1. Data Model: Amazon DynamoDB is a document-based NoSQL database, meaning it stores structured data in JSON-like documents. It offers a key-value model with optional secondary indexes. On the other hand, Neo4j is a graph database that represents data as nodes, relationships between nodes, and properties associated with nodes and relationships. It enables high-performance graph traversal and complex querying.

2. Querying Abilities: DynamoDB offers simple querying capabilities using primary keys and secondary indexes. It supports basic CRUD operations and can perform range queries on numeric and string attributes. In contrast, Neo4j provides powerful graph querying capabilities that allow traversing complex relationships and patterns. It supports graph-oriented queries to find paths, shortest paths, common nodes, and more.

3. Scalability: DynamoDB is a fully managed, highly scalable database that automatically scales horizontally without downtime. It can handle large volumes of traffic and offer low latency with automatic data replication across multiple availability zones. Neo4j, on the other hand, is designed to work on a single server or cluster and requires manual scaling to handle high loads.

4. ACID Compliance: DynamoDB ensures Atomicity, Consistency, Isolation, and Durability (ACID) properties only within a single partition or item. It does not guarantee ACID across multiple partitions or items. On the other hand, Neo4j offers transactional consistency on a global scale, allowing ACID operations across the entire dataset.

5. Data Relationships: DynamoDB does not have built-in support for relationships between different items. It is primarily designed for key-value data storage. In contrast, Neo4j's graph database model is specifically designed to handle complex relationships between entities. It allows developers to define relationships between nodes and perform efficient queries based on those relationships.

6. Use Cases: Due to its document-based structure, DynamoDB is suitable for applications with predominantly read-heavy workloads and simple data access patterns. It is commonly used for real-time applications, gaming, and content management systems. Neo4j, with its graph database capabilities, is ideal for applications that heavily rely on analyzing and querying complex relationships, such as social networks, fraud detection, recommendation systems, and knowledge graphs.

In Summary, Amazon DynamoDB is a scalable, document-based NoSQL database with key-value storage, while Neo4j is a powerful graph database with extensive graph querying capabilities and support for relationships. DynamoDB is suitable for read-heavy workloads and simple data access patterns, whereas Neo4j excels in applications with complex relationship analysis and querying requirements.