Well, I'll say that the event certainly won't completely overlap with any other events. It kind of is in a league of its own. But just to add, I'd say earth science or physics-like events, like circuits, geomaps, dyplan, TPS, study portion of maglev, maybe parts of matsci, remote, thermo, rocks, you may liken with it. Not necessarily for the exact overlap in the aspect of concepts or format, but the general aspect that it is studying physical processes that are quite interesting. Fermi is the other event which also has the overlap of very large or small numbers.
In general, it is always best to just take a look at all the events, and see which ones interest you. Sometimes you may like astronomy, but you find that another unrelated event you like. I know Alpha has done Forensics, and I've done Microbes, so it's up to you.
B: Crave the Wave, Environmental Chemistry, Robo-Cross, Meteorology, Physical Science Lab, Solar System, DyPlan (E and V), Shock Value
C: Microbe Mission, DyPlan (Earth's Fresh Waters), Fermi Questions, GeoMaps, Gravity Vehicle, Scrambler, Rocks, Astronomy
Grad: Writing Tests/Supervising (NY/MI)