I stopped using them a while ago but for a different reason. I used to use their website to check availability/whois for domains that I was interested in buying. If it was available I didn't buy it at the time but until I finished the website/app whatever I was going to put there, this took me a few months obviously. It happened to me that when I was finally ready the domain had already been sold to someone else. This repeated five times during six or so years. Now, I know, "someone else could have thought the same thing" but I find it very hard to believe that it happens so often. These domains were a bit of niche words that were not hot topics at the time, some of them using fairly uncommon TLDs (like .one). Another weird thing is that they were always registered to someone living/or doing business at India, and it was a fairly simple landing page with a "contact me" link. I'm a bit superstitious so I don't think it was a coincidence.
Now, I don't think this is a GANDI problem per se, but my theory is that they share this information (who is looking for which domains) with marketers or something like that, or maybe it was a rogue employee trying to make some money squatting domains. I would have expected this from BigDaddy or similar sharks, but from a company whose motto is "no bullshit" I had much better hope. Anyway, I decided to move (to namecheap if you're wondering) and surprisingly the problem went away.