LMMS is a comprehensive DAW that supports both MIDI and audio, making it suitable for full music production, whereas Sekaiju is focused solely on MIDI composition and is best for creating and editing MIDI files.
LMMS
Pros:
Free and open-source
Multi-platform support (Windows, macOS, Linux)
Wide range of built-in instruments and effects
User-friendly interface for music production
Supports MIDI and audio recording
Cons:
Can be resource-intensive
Limited documentation compared to some commercial DAWs
Not as many features as professional-grade software