Old post, but still popping up in google. My two cents: I have used Cuban sugar, different types of honey, and rock sugar is still my favorite. While the price is steep, the flavor does make an incredible difference. I am an avid tea drinker and brew tea all day- more than a hobby, it helps me focus, enjoy, and smile more often. I often brew the tea with the rock sugar at the bottom of the infuser, so it actually dissolves as the tea is being made and not when you're about to drink it. Another way I like to use it is to fill up my 32 oz thermos with the sugar at the bottom, let it take its course for a while, then flip the thermos upside down, slowly, so it can sweeten the rest. I use about 4 teaspoons per 32oz, which makes it just right for my taste. I have never tried using the sugar at the bottom of the mug, as I drink little bits at a time (remember, all day).
Like with anything else, there are different types of sweet. Rock sugar, although I buy plenty, I only use for tea, since it's the kind of sweet I enjoy the most on teas. It is cane sugar, just processed differently. If you really want to know the difference, pass by a Teavana and ask them for a small sample (you can order cheaper sugar online). Your mouth will understand. I don't personally oppose tradition, as I enjoy it quite a bit, but I don't mind trying new things and improving older measures. This is our time for us to live, right now, not then or later, so I believe breaking tradition is as important as studying it.
A smaller note: if you use a Teavana tea maker or something to that effect and place the sugar at the bottom with the tea while it brews, and you serve it straight out of it and into the cup, the first cup will be sweet, and the second one will not even be aware there was sugar ever involved. It's only a tiny annoyance that can be quickly fixed.