As far as sellers go, I had GREAT experiences (outstanding quality & creativity), as well as a couple that were a total waste of time and money. I am still waiting for Fiverr to give me a refund on one I didn't want to give a positive rating to, because I was not satisfied with the product. Most gigs are more than the advertised $5, but in reality - someone designing an awesome logo for $20 is a hell of a good deal.
That said - the reason I would NOT recommend use of Fiverr is because since I have used it, the credit cards I used on the site were hacked. None of my other cards have been hacked; just the ones I used on Fiverr. Large purchases were made for car repairs, "donations", large amounts for Facebook advertising, and several others that were declined. Coincidence that ONLY the cards I used on Fiverr were hacked, and within two weeks of the purchases being made? Maybe - but after that hassle of having to cancel cards and sign declarations I wasn't buying car repairs out of the country... I won't be using, or recommending them anytime soon.