I suppose it depends on how you're thinking about your instruments and what you need for your piece.
If you put them together, you'll conceive of the music for them as a singular unit. If you separate them, you'll likely think of each instrument as a more independent entity. The effect here is how you envision your percussion to function: is it just to provide a simple backing, or are you going to be writing incredibly complex parts for each instrument that requires they be independent?
Since I primarily write acoustic music, I think of the people performing what I write. Your questions is similar to: all instruments on a staff, or multiple staves?
So for me, because I deal with people (though I have a lot of work that uses electronics, and I myself also use FL Studio for some of my work), separating instruments also serves a practical / logistical function:
If I group my instruments together, I need to think about how much time it takes for the player to actually play each instrument, to switch between them, to switch mallets, and the coordination of playing multiple instruments simultaneously. I also need to think about choosing instruments that aren't too difficult to find or are a pain to lug around. If I separate the instruments out, then I need more percussionists, which costs more $$.
Since you're primarily electronic, you have a couple different considerations: your own workflow. Before FL Studio created that thing where you can see other patterns on the piano roll, it was a nightmare for me to bounce between instruments because I couldn't see all the music at the same time. So the advantage to grouping there is that you can see everything at once.
Moral of the story, ask yourself these two questions: "What does my piece need?" and "What do I need?"