Just a note, since I’ve seen some people confused by the terminology. “Star” when discussing power supplies for modular (and in some other contexts too) is a reference to the physical design and layout of the board, not a rating of quality or something. Star topologies put the central ground physically near the middle of the board, and directly run each output’s ground line to that central point. “Flying busses” link the furthest module’s ground through the next furthest, and so forth until you reach the main ground point on the PSU. The difference is that in a “star” grounding system, high currents and ground noise affect the other modules less, since they are not in a chain on the same wire.
Now, if your modules are well behaved and don’t draw a lot of current, a flying bus can be just fine. Or, if you pay attention to the current draw and put your higher current modules on the side closest to the PSU connection, you can also mitigate this problem to a large degree. But for situations where certain modules are particularly noisy or everything pulls a reasonable amount of power (e.g. more than a few tens of milliwatts) then you may gain by using a star topology. You might also gain by using a separate PSU for the very noisy modules, if you’re really in love with them and want them to calm down a bit. In that case the flying buses might still be just fine for the other modules. YMMV.
