Marshelangelo,
I have used a lot of both, but for different applications.
Pink Insulation Foam Board:
• Great for building scenery such as mountains, rock formations, tunnel portals, retaining walls, etc.
• Easy to cut with a knife, hot wire, band saw, table saw, etc.
• Paint with latex paints, and glued with spray adhesives.
• Not good for sound absorption. (Will not make any track quieter.)
• Will not hold nails or screws. (And there are a lot of things, other than track, that will require to be screwed to the layout surface.)
• Not good to be walked on, and will dent and scratch easily.
Homasote or sound board such as QuietBrace from Home Depot (half the cost of Homasote)
• Great for sound deadening.
• Can be walked on.
• Resist denting and scratching to a certain degree.
• Can be painted with anything and glued with almost anything as well.
• Will hold nails and screws; not like wood, but good enough for most purposes.
Good luck!
Alex
