I hear the Crimson and Titan similarly to how they were graphed by BGGAR. The main differences are pretty much what
@domq422 described.
The Titan's DD bass is just visceral. There have been times when listening to bass-heavy tracks where I can feel the sub bass in my feet as if there was a subwoofer nearby. I know it's all in my head, but it's still a crazy sensation that I've never felt with the Crimson. What's impressive is that it does this while still sounding clean and smooth.
The Crimson is the more balanced set though. It still has good quality bass, but there's less in comparison. What's impressive here is that its BA bass sounds better than a lot of single DD and hybrid sets that I've listened to. Mids and vocals are similar to the Crimson - they're both clean and smooth, neither are recessed or in your face.
Treble extension is really great on both sets, but the Crimson is a step up. Hi-hat and cymbal crashes sound airy and they decay nicely. The Titan is no slouch either, but the Crimson just does it a bit better. For soundstage and imaging, I really can't tell the difference between the two. They both have a pretty wide open soundstage where you can hear the music in layers and what some people would describe as "holographic."
I love them both, but if you're like me and like your bass to be boosted on bass-heavy tracks then you might like the Titan more.