I've shot one HFT season with them in a AA S400 when lead pellets were banned at the range we used to shoot our nationals. We tested a lot of them both the SN-1 and the PCP-1.
Up to 40 meters they were quite okay. 40 to 50 meters they group minimum twice as big as the JSB Exact. Never shot smaller groups indoor at 50 meters than say 2 inch.
So for HFT theyt might do when lead is banned for some reason. For FT up to 50 meters they are useless.
When we changed to a new shooting range were lead is collected from the bullettraps behind the FT targets I never touched them again.
Some people reported that they only shoot well in a very clean barrel, one that has no traces of lead in it. But tried that and never saw any improvement over a barrel that was not cleaned.
So if you're not obliged to use these non-lead pellets it is better to stay away.