.NET Native addresses many of the same issues as Mono AOT but it has a radically different basis. We had the advantage of hindsight :)
The biggest difference with NGen is the fact that .NET Native doesn't ever "fall back" to JIT compiled code. There are other differences--refactored runtime, static-optimized libraries, static marshalling, etc.--which can be seen by the perf wins over NGen. We're seeing 40% startup performance gain over NGen apps for top Windows Store apps.