I've been using Easy Curves on and off (currently "on" again now) for over a year, and I like it a lot! It makes your cleavage area a little more plump right away.
I do like the bodybuilders do, and I follow my Easy Curves exercises with a protein drink. Just make sure you set the resistance to a level that seems pretty easy when you do the first few reps; but by the time you get to 10 or 20 reps in a certain exercise you're kinda feeling the burn JUST a little. Any harder than that, and you'd probably risk burning off the fat, as had been mentioned already. I started at "1"; and right now I'm staying at "3" (I'm a weakling, lol). I tried "4" for a while last fall, but I think it was counterproductive. I did "5" once, and it made me pull a muscle in my chest that hurt for like five days.
Make sure you keep your shoulders back; and really concentrate on flexing your chest muscles instead of the muscles in your arms when you do the reps. Sometimes, if I'm having a hard time feeling my chest muscles flexing, I tighten my abs; and for some reason, that puts more emphasis on the chest muscles to work. I don't know why it helps, but it does. Also, going slower seems to work better than whizzing right through it in a couple minutes. By the fifth or sixth day of using it, I notice that my breasts feel really tingly and "alive" for quite awhile after finishing the exercises. It feels nice, like something is actually happening in there.
Maybe adding some heat for awhile afterwards would help maintain the extra bloodflow for a little bit longer ... I don't know, I'll have to try that sometime. Be sure to stretch the muscles out across your chest before and after using it. Personally, I just stand in a doorway with one hand on each side of the door frame; and I take a couple steps through the doorway while my hands are holding onto the frame, stretching my arms back behind me. That really stretches those chest muscles good! And then hold my hands real high above my head, and lean toward the left; then lean toward the right. I like that Easy Curves is really easy to use, and doesn't take up much space. Five or ten minutes once a day is all that it requires.
Wow, I realized I sounded like a commercial.
Sorry! Just wanted to share my experience.