The item will draw what current it needs (As long as it is well!) Bigger than minimum required is better and usually less stress on the power supply.
But bigger is almost always more expensive with power supplies. Buying something in the next range up from the actual specification of the device can cost another $10-20.
For best efficiency, you want the current to be at least 10-15% below the maximum and 10-15% above 0. At either end of the range, the efficiency of the power supply drops off, sometimes quite dramatically. My old 220 watt laptop power supply always drew at least 15 watts even when it was unplugged from the laptop, which was a pain - it should have gone down to near 0 watts. You do not want that sort of problem, as 15 watts 24x7 all year adds up to $$ on your electricity bill. Similarly, if you have a 20 watt power supply and are running it always at 19-20 watts, you might find that it is drawing 50 watts from the mains to do that, but if it is only running at 15 watts, it may draw 18 watts from the mains. And the rest of those watts will be being dissipated in the power supply, so it will run very hot and fail early.
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