Dummies are by far the best invention for mankind. I hope that whomever invented them was filthy stinking rich and that their family still benefits. I would go MAD without dummies here.
My kids are comfort suckers and they lvoe their dummies. DS is nearly 2 and the only time he uses a dummy is when he goes to bed, and for long car trips (where he will sometimes fall asleep). Life savers really and have made my kids far less stressed out(and mummy and daddy are pretty chilled too).

Dummies have played no part in any infections, speech issues, or even breastfeeding issues. I have no problem with my kids switching between boob and dummy.

I don't see the harm in them at all. I am all for dummies!!

Ooo I forgot to add, dummies were introduced on day 3 with both of my kids