I have never used micro spikes,
but it is my impression they are mainly for on trail, on sidewalk stuff, like winter trail running.
I would not use them for anything resembling mountains.
Regarding the Aluminum v.s Steel Kahtoola KTS ...
I went with the steel mainly because the spikes are a 1/4 inch longer, closer to real crampons.
in mountain travel you may sometimes travel over a mix of ice, snow, and rock.
the travel over rock will destroy the aluminum much quicker then the steel, so you are faced with removing the crampons each time you come to some short rock travel.
but if you are only going to use them a few times, the weight saving of aluminum may be a factor.