What sort of distance is 1 unit in unity? I was under the impression that 1 unit is equal to 1 meter, but after making a model and importing it at a scale of 1, my impression no longer stands the same.
As far as I know the default is 1 unit = 1 metre, but in fact the unit in Unity is just a unit, which needs to be defined as such.
Although by default gravity and audio doppler settings relate to 1 unit being equal to 1 metre.
You made a model in an external app and imported into Unity and you’re trying to base the length of a unit in Unity on that? How would that work? 
Anyway, like Meltdown said 1 unit is generic. Some parts of Unity sees it as 1 unit = 1 meter for their default settings, but you can easily make a 1000x1000x1000 cube behave like a suger cube by tweaking things like gravity and mass. It’s up to you to define what 1 unit is.
I know from experience that if you use meters in 3ds max then 1m in 3ds max is the same as 1 unit in Unity. But the FBX importer sets the import scale to 0.01 by default so setting that to 1 and you could say that 1cm in max is 1 unit in Unity. Either way it’s up to you to choose something that works for you.
Cheers guys, appreciate the answers!