Peach can't usmash the platform. She can only do this at the very high point on both slants on the ground when the stage is flying, which is very insignicant.
And as for sharking... I'd wait out peach's float by camping the higher platforms or attempting to dtilt spiker her head if it's popping up. Her sharking game isn't as potent as MK's or Jigglupuff's imo on this stage as she'll either be in a position to be dtilt spiked or Dsmash'd or she can be 'waited out' so that she's forced to use her second jump or recovery or go back to the ledge.
edit: everyone types faster than me!
but pretty much what darky said - except I feel early usmash kills from zelda and later Fair kills from peach make this an okay stage. There could be better options though.
And as for sharking... I'd wait out peach's float by camping the higher platforms or attempting to dtilt spiker her head if it's popping up. Her sharking game isn't as potent as MK's or Jigglupuff's imo on this stage as she'll either be in a position to be dtilt spiked or Dsmash'd or she can be 'waited out' so that she's forced to use her second jump or recovery or go back to the ledge.
edit: everyone types faster than me!
but pretty much what darky said - except I feel early usmash kills from zelda and later Fair kills from peach make this an okay stage. There could be better options though.