Semi metal resin pads have pros and cons, the pro is that they do stop better in less the idea weather conditions, BUT the con is they don't stop as well in dry conditions and are subject to brake fade under hot conditions, and that heat could come from outside temperature or from excessive braking like running down mountain roads. So unless you'll be riding in a lot of rain type of conditions or mud stay with organic pads like the ones that Shimano has.
Another con to semi metal pads is that due to the metal it will wear out your rotors faster.
So you have to get the brake pads that are suited for your riding conditions.
Most suggestions are for the average rider who won't ride much in the rain and doesn't ride in muddy conditions, and the suggestion is that organic pads are the best all around pad.