I was a member of Fiverr as a seller but had a gig that never sold. Then, I decided to get serious about Fiverr and found a way to start with smaller cheaper gigs and work my way up. I now get $100+ for most of my gigs, I have 121 5* reviews, I'm a 2nd level seller, and I've made almost $7,000 in 11 months. This helps supplement my full-time local business with business that I get from all over the world.
Yes, sometimes customer service isn't exceptional. There's an occasional scammy buyer or some seller throws an offer at me without so much as a "hello" -- but that's the fault of people, not the platform. I don't have a monthly fee to Fiverr, I don't have to pay to pass tests to qualify for gigs, they don't charge me their fee when I land a client on Fiverr. I get great reviews and many repeat customers because I over-deliver.
Update 3/6/17: A few updates, now over $10.5K on Fiverr. 193 reviews. 237 orders. 19 cancellations. Profile: eclectictllc
In reading more reviews and complaints about Fiverr: I won't say Fiverr support are angels, because that's untrue. Make sure you're paying a reasonable amount for what you're going to get, and maybe you'll get higher quality sellers. If you go to Fiverr thinking you can get a whole novel edited for $5 only $4 of which goes to the seller, what do you expect the quality of the work to be? You have a huge pool of talent, and the more talented people are going to demand a better price for their work. You do truly get what you pay for. If you think that Fiverr staff are terribly motivated on behalf of $5 buyers who are out to rip off sellers, you're probably wrong. There are many buyers who are dedicated repeat customers on Fiverr, and do large projects with sellers. I know, because I'm one of them. And I know other people in my local business community who have built up relationships with Fiverr sellers. Find someone, vet them, talk to them, start with a small project and then work up -- both in size of project and fee scale -- to larger projects with your trusted sellers. It's how you create a relationship ANYWHERE in the business world. And Fiverr and Fiverr sellers are businesspeople.