Ron, I've been involved about 10 landfill courses and can relate to Mike's learning curve. 1st, by landfill, in the states that refers to a Sanitary or Garbage dump site (I've heard soil brought in from off-site as "Landfill" in England). We builtand operated on for 15 yrsso I became intimate with how much different these are than courses built on in-situ sites. In a nutshell - they move, constantly. We used to joke, iyou never get bored with the greens 'cause the contours are different every year.
Although easch site is different in compostition, perhaps the one constant is they tend to require more repair projects mainly in drainage and irigation. Because they are capped with an impervious material, water doesn't "soak in" and when the gound settles, underground piping can loose positive pitch and basins can no longer be in low spots.
From a design standpoint, you have to know what to expect and design to accommodate it in the future. Not beng able to "cut" and having to rely on just fill (and poor quality fill) forces one to get really creative.
But on the positive side, after a while, all that settling tends to create some very cool and natural looking contours.
I just finished one up in Indiana (just outside Chicago) and have one on the boards for Helsinki. Plus I just finished a hole with a 40' landfill right in the middle of a par 5 that needed a HDPE liner.