I like that it has tons (literally) to choose form so you can find what works best with your customers/brand & product line as well!! It also makes creating new campaigns very easy because there are templates all over this site which saves time.
Sometimes searching through pages gets tedious but at least they have an autocomplete feature once someone types part or almost everything into their search bar - GREAT SITE. ! Highly recommend using whoismailingwhat website when looking up mailing list options suchas customer emails / addresses etcetc.