Hi Skyjumper,
A platform bed is generally fine for a memory foam mattress or a latex mattress as long as the slats are strong enough and close enough together to be suitable for your mattress and there is good center support to the floor in the middle of the platform bed to keep it from sagging under the mattress. They can also be used with a suitable foundation if you need extra height.
If your platform bed has a solid surface instead of slats (which provides less airflow under the mattress) then post #10 here may be worth reading as well.
Phoenix