We have a band room around 4 by 5 meters. It's better to keep instruments more quiet in such a small space for better readability of any single instrument. These cymbals help a lot in this case. They are impossible to play loud.
Pros:
- they are quiet (like really-really quiet). I can smash the crashes with my full power and they still will be quieter than toms/snare drum
- they are cheap. I put them on the drumkit and I don't care if bass player or guitarist plays them
- they are light! easy to carry around
- look a bit like cheese, if you like cheese like me, that's a bonus
Cons:
- the edges of the holes are not very neat. I actually cut my skin on an index finger by simple carrying ride cymbal with it (using it kind of like a stand). That's usually not a problem with normal cymbals
- the sound is more on a hissing side, hi-hat sounds especially nasty when open. In my opinion, they are not good for recording or any kind of live situation (at least for music I am playing). Might be good only if loudness is an issue, but you might also just take lighter sticks/play quieter and not sacrifice sound quality of normal concert cymbal set.
Overall, good inside a small room. Not good for recordings or concerts.