I don't have a recommendation, just some thoughts. I use to deep sea fish weekly and have grilled a lot of fish. I have used several different fish grill baskets and never found one that justified the effort of cleaning over a spatula. I use one every once in a while for grilling vegies, quite handy for that.
For purchasing one, size, in all three dimensions, drove my decision.
{edit} On reflection, there was one instance where the basket worked very well. I had some nice Yellowtail fillets. I also had a bunch (several pounds) of fresh rosemary which I soaked in a bucket of water. I layered about 1-1/2 inches of rosemary, the fillets, then an equal amount of rosemary and clamped it in the basket. It steamed and smoked the fillets very nicely, and obviously made flipping easy. I loved the result, but SWMBO declared she was not a fan of rosemary. So much for that. :sad: