Side effects questions

I have a one drop yoyo and am curious as to the effects of different side effects (I have a kuntosh that came with flat effects).

other than aesthetics, what is the effect of heavy vs light side effects? Do the different shapes (spikes vs. flat vs. rounded etc) allow for different types of tricks? Anything else i should consider?

thanks

Weight is the big thing, however you can pinch the yoyo between spikes and use them like hubstacks.

The flat side effects are fairly light. How does play get affected by switching in the heavy brass effects?