Can't answer your breed/feathering question because, well, I really don't know. But as to the first part of your post - here's where the heat lamp has a partial advantage over Mama Heating Pad. (ooooh, did I say THAT?) With a heat lamp, the minute the power comes back on, so does the heat lamp. If you're using MHP, you have to go out, turn it back on, and remember to hit the Stay On switch. Now, that depends, of course, on which heating pad you are using. If you are using the one that @henless
and a few others have, it turns itself back on. But most don't.
However - when that heat lamp goes out the entire brooder temperature drops. Not so with Mama Heating Pad. The majority of the brooder remains exactly the same temperature it was when power was lost, and the "cave" will retain enough heat to sustain the chicks surprisingly well, especially if they are cuddled together under it. The small space makes it easier to hold heat. Also when the heat lamp goes out suddenly, chicks who are used to 24 hour light are suddenly plunged into darkness AND chill at the same time. So I guess the score is still MHP ahead by 4!