Are two smaller subs better than one larger?

It depends. In general one larger sub will have more low-end extension than two smaller ones, but two smaller will be a bit faster than a single larger cone. 2 subs allow stereo separation above the point at which bass begins to become directional (about 60hz). Two subs also allow for a more even, across-the-room distribution of bass, but one can at least be tuned to the listening position very well. Your crossover point will determine a lot on the point about stereo separation - from the range of somewhere around 80 to 100hz and higher, you should maybe be thinking of 2 subs, anything below that and you can be thinking about one. Cheers!

Yes, in my experience, in my room. I had tried a single, 15 inch driven by 500 watt sub amp, but it did not provide the impact I thought was possible. So, I switched to smaller units. Sold off the 'big boy'. Could not be happier. Lastly. The room makes a huge difference so you will need to tweak placement to get the best effect of two units.

For music definitely yes.

Another resounding YES.