It was reasonably light, as I recall, since it is a single-action (e.g. it is fully cocked by cycling the slide, and the trigger just releases the sear). I couldn't find any technical data sheets on the MP-25, but I'm guessing it was roughly comparable to or slightly heavier than other single-action guns, e.g. Ruger Standard Model semiauto, or a single-action revolver. I saw a guesstimate of a 6-pound pull on another forum, which sounds close enough.
To clarify on the safety, my ex's was the kind that slid up and down (and locked the slide), not the older Raven Arms style that slid forward and back. it wasn't that it was so light that it would just "fall down" on its own; it was simply that in a pocket or something, the resistance of the safety could be overcome by getting snagged on something or by being bumped/pushed by a hard object. I *think* the factory manual recommended carrying without a round in the chamber and chambering a round when ready to fire, but it's been many years since I looked at it. I am pretty sure it didn't have a passive firing pin safety, as it was designed to be carried unchambered.
I have to say that it was 100% reliable (no failures of any kind), and my ex shot hers quite a bit. It was also (surprisingly) very accurate for its size, a consequence of the fixed barrel and tiny sights (very precise, but slow to acquire). Fit and finish was rather good; it wasn't sloppily made, just very bulky for its caliber and capacity.