Puff 'n' Stuff Geyser makes a lot of noise, but doesn't seem to do much else! The eruptions are only a few feet high and often send a fine mist down the boardwalk after you. Around about the cone, there is often a build-up of a light grey-blue clay, presumeable formed by the interaction of the underlying rock with the hot mineralised fluids erupting from the vent. The run-off from Puff'n'Stuff cools rapidly and plants quickly colonise this channel.
This can be a good place to sit and watch dragonflies darting around :)