MailRush is limited to email. Use more channels to get more replies.
MailRush is good for cold email but you should never stop at cold email. If you include website messages, calling, and LinkedIn, the number of replies you can receive will increase dramatically. If you want to do more than cold email, then LeadLoft is likely the better option.
MailRush.io is an email service provider and email automation tool for B2B cold email outreach.