Neo4j 1.7 Milestone 2 introduces several significant advances, including a new cache scheme that is GC resistant and 10x faster, targeted pattern matching in Cypher, and Debian install packages. The Atomic Array Cache (AAC) is a key innovation that prevents garbage collection from collecting anything in the cache without explicit management by Neo4j, resulting in no GC pauses when configured correctly. Additionally, Cypher now supports multiple relationship types within a single relationship segment, enabling more complex queries. The release also makes it easier to install and deploy Neo4j on Debian-based Linux distros with a simple `apt-get` command.