My preference for single pots is that some things like Utrics are
invasive. You can also take things out more easily for show and tell.
Also bug problems are easier to deal with. Sure, you don't get the
neato community planting look, but I think you could get around this
if you wanted. For example, I once set plants (in pots) into a terrarium
filled with Sphagnum.
Eventually I tired of this and now just keep plants in pots in terraria,
without any pretenses to community planting looks.
B