what do you mean compression springs on the deck?
It does best in thick, lush lawns, but it will cut other stuff too. Did you verify the deck was properly set up? I have messed with mine a lot and have got it cutting decently. I only have real problems on thin yards or very fine bladed wiry grasses. Usually on those I drop the height down to 3'' or less and it does ok. The stock blades are only good for the thick grass, I run the Scag medium lift blades and have good luck with those