In most cases they will give you 'replacement value' on your belongings. So if you have a 3808 for instance that you paid $1400 dollars for when you bought it new, but now you can get one for $1000 dollars, they will give you $1000 dollars. That's what surprised me when I took my claim to HH Gregg and they gave me $1400 dollars instore credit when the exact same TV I had only cost $700 by then.
I don't know what Monster's guarantee is though. It would be sweet if you could get both companies to reimburse you!