Just makes sure you’re not switching saddles to get around an underlying issue, consisting of a saddle that’s too high or too far back, or handlebars that are too low or too far in front of you.
Try pushing the saddle down and forward and see how your perineum/labia feels. If the saddle is slowly splitting your sit bones apart, it’s too narrow.
If you get a bike fit and they begin applying a template (measurements/formulas/angles), they’re wrong. Find another fitter or experiment yourself.
In my opinion, ISM saddles are more comfortable when you get impaled because of a faulty bike fit. They are also good when getting around the UCI rule of “tip of the saddle 5 cm behind bottom bracket”. Besides that, they’re a gimmick.