We do NOT use or recommend foam containing pits for a number of reasons.
The first being kid safety. Inflatable foam pits usually only have one entrance and one exit, and while foam is awesome, we do want kiddos to be able to get out of it easily if they are scared or otherwise.
Secondly, a pit will become very slippery and if someone falls down, is injured, or worse, the walls will block your vision and not allow proper supervision or aid in the event of an emergency.
The foam maintains its own shape and kids just love being able to run into and out of a huge pile of foam from all directions.