InboxPro offers Free Trial, but GMass does not.
InboxPro is designed for Large Enterprises, Medium Business and Small Business.
GMass is designed for Large Enterprises, Medium Business and Small Business.
The starting price of InboxPro begins at $7.49/User/Month when Billed Yearly, while pricing details for GMass are unavailable.
Some top alternatives to InboxPro includes GMass, AutoPitch, SmartWriter, Mixmax, Ghostwrite, Qualified, SmartReach.io, Workvivo, Sigmail, IFTTT and Consider.
Some top alternatives to GMass includes Campaigner, Moosend and SMTP.