rob--the whole idea of sweetening is to balance the acids. When you have the acids balanced with the correct amount of sugar, it does not cover up the flavor--it enhances and draws out flavors that are hidden.
If you over-sweeten, then you can start to lose flavor. Very similar to tomato sauce--get the correct amount of sugar in it and it tastes nicely balanced and not too tart. Get too much sugar in it and the flavor goes south.
We always use sugar and are very careful with more delicate flavors, like peach. Get peach too sweet and the flavor is tamped down. Much of this is from experience and it's always a good idea to go by SG, otherwise what tastes good while bottling sometimes gets too sweet when you open the bottle 1 month from bottling. Do some experimenting with sugar on your wines--you'll soon find your happy place. Take the SG of what seems to taste good to you and write it down. Then evaluate it when you open the bottle--revise your SG if it's a tad too sweet, or not sweet enough, and use less or more sugar next time and take note of SG.
We've used this practice over the years on every wine we make and the notes come in very handy year after year so we don't have to try and figure it out again.
