I think cozy is right. Both have there advantages.But I dont think you will get a 'straight' answer on here.
BUT IMO Its Leaflets all the way. Get a job from a leaflet then Do a top notch job AND I MEAN TOP NOTCH!! (more than is expected of you) and you will get the compact work quicker than you think. 99% less messers with leaflets (IMO).
IMO. Dont use a multi/slid in a newspaper leaflet drop.
But defo Re-leaflet targeted areas every 2 to 3 weeks.
Could tell you more but that would be giving my secerets away