I am stuck on which one I should go for
Both can be used to achieve a cleaner mix-down, so it will depend on what you want or need to do specifically.
If you have two elements colliding in the mix (very common with the kick drum and the bass) you can make one lower the amplitude of the other. In this case you are looking for sidechain compression.
In the other hand, if you are looking for an element to sound only in specific circumstances, you are looking for sidechain gating. Like on a track that contains a complete drum loop, if you want to hear the snare only you can set the control signal to be a high-passed version of the input. Or you can set one element to trigger another one.
which of these would be recommend in reference to side-chaining my snare to my synths for a cleaner mix-down?
In that specific case it sounds that you want sidechain compression in the synths with the snare as the control signal, so the snare lowers the amplitude of the synths so it cuts better through the mix.
I simply want to dodge the fighting frequencies so it will sound much clearer!
In that specific case you want to check which frequencies are colliding and apply sidechain compression only on those bands using a multiband compressor.