I have always had a triple (well, if you don't count my 3, 5, and 10 speed bikes from a long time ago). I spend most of my time in the middle ring, using the other rings as described. I live in a hilly area and I shift down to the granny well ahead of a steep climb. I do use the big ring on flats, but there's never much extended flat areas where I ride. Plus, I find the more time I spend in the big ring, the more my knees feel a little "jacked."
I use all of my cogs in the middle gear. I have Ultegra and have never had a problem. I rarely drop my chain. There are some smaller hills that I climb in the easiest or second easiest cog/middle ring combo and there's just no issue. In fact, when I switched from a 25 to 27, I started doing this immediately.