Both of mine have a very nice/positive click going from safe to fire and a slightly less loud click going from fire to safe.
Several people here have reported losing that little piece of plastic (not the spring so often, but the spring alone won't make it work correctly) when removing the safety to do other work, or switching between decocker and safety. That piece of plastic is behind/inside the left side safety. You have to remove the left side safety to see it.
I don't think this is my picture (don't want to take credit for someone else's picture/work) but this is what it should look like (back side of the left side safety on the omega pistols).
You can see how the little piece of plastic fits between the shaft of the safety and the little metal pin on the back of it. The spring is down in a hole in the shaft of the safety. The click is from the pointed end of the plastic piece being moved up/down in reference to the metal pin when you move the safety from safe to fire and back.