I've been on Gratify since Dec 2016. I was hired through Gratify and used it to hire freelancers myself.
Gratify really feels different than other marketplaces. You get a private Slack channel to discuss with your client/freelancer after you are matched. The connection is real and you get to develop a stronger relationship based on human interaction.
Everything happens on Slack, so if you are already using Slack you don't need to interrupt your day to track what's happening on your open projects.
You have an immediate access to hundreds of vetted experts by simply typing "new task" - and that's priceless when you need a job done, but don't have specific expertise or your local team is busy. I've tried to use Upwork and Fiverr for outsourcing small tasks before, but there's nothing to compare with Gratify, which just saves a lot of time and nerves