I also use IceSpikes.  I find they last longer than screws and they are easier to put in.  But they are more expensive than screws, obviously.

What I like about IceSpikes is I can easily run over dry pavement with them.  That wears them down quicker, and you can hear the click-click, but they otherwise do fine over dry pavement.  A lot of my running is going back and forth between snow, ice, and dry pavement.  They are very light and have the least effect on your stride.

Three pairs of shoes:  treadmill/track shoes with foot pod for indoors, pair of shoes with IceSpikes for snow/ice, and a pair of regular road shoes for running outdoors when it is clear.  I have pulled out the IceSpikes no problem, but I leave them in for the season in one set of shoes.