Hi,
Check this thread about resin formulations and compatibility.
Also I think your firmware version must be up to date (at least the version where BlackV4 was introduced).
Usually, you can’t buy more Black V3 since they clear the stock before starting new formulations.
What I’ve personally noticed was a slight better surface finish (also changed printer, so not sure it is about the resin), and a little more flexible parts, especially the support structures. But overall, its the same.
CPinto