Hmm. I have always blipped, on instinct I guess, because I like to have the engine where it is always 'engaged' and to know exactly where it's at. All bikes are different as to the exact RPM, but i always try to have the bike close to the RPM where there is enough torque or compression going through to the back wheel for best traction forwhatever is needed, accelerating or braking.
Having said that I do need to be more careful with the CBR250R as 1st gear is so low, I have skidded the back wheel out once or twice. But that mainly happens when I am not being mindful. Coming into a light or a tight corner I blip down fairly quckly, just feeling the traction enough before going down again. On the occasion that i have stupidly skidded the back wheel out I just was on "automatic".
Coasting for me is what I do on a gentle slope at slow speed down from my house when I am warming the bike up and don't feel like sitting around. Otherwise, as Auffit puts it, "angel gear" is just not being in control of the bike. A lot of people in Indonesia - village people, farmers, girls on the way to school - do the angel gear thing to save gas, often cutting the engine. It's hairy and scary to watch them flying down a hill side and then suddenly have to stomp on the brake or squeeze the lever because of something just popping up. At that point all I do is pray for them.