Drum Replacer

Drum replacer is an ARA plugin (besides Melodyne, its the first native ARA plugin in the industry). 
At this time it will be only available to Platinum customers. Its possible that we might make it available as a paid update to Studio or Artist customers, but at that point maybe its better to just crossgrade to platinum :)
The main advantage of ARA in the context of DR is that it has full access to the audio, allowing it to do its hit analysis ahead of time and thereby have zero latency triggering.
 
Even if it were allowed to work in other ARA capable DAW's, SONAR is the only DAW that has generic ARA support. i.e it works with any ARA plugin and not just Melodyne.  (AFIK Studio One is locked to Melodyne only)
While it could have potentially used in SONAR X3, it wouldn't work properly since there have been many advancements in Platinum's ARA implementation as well as other features that DR depends on. For example DR needs access to the project audio folder to save data, etc.
 
DR has been in development for a long time - close to a year. We put a lot of effort into stability and making it work well out of the box so we're excited to see how users like it - I think with DR we have the most intuitive and integrated drum replacement solution in the industry. It has some creative applications even outside of the primary drum replacement function. You can use it on any percussive material to fatten or add another percussive voice to it. Imagine taking a guitar part and adding automatic percussion hits to the accents or even blending in a new attack sound with it. Or you can drag out MIDI from a DR clip and send it to a synth...
 
Even if you aren't a platinum user with access to DR, the good news is that there have been numerous bug fixes and enhancements to the ARA code, making even Melodyne work better in SONAR!