Dean,
Like all devices there will be limitations and I'm thinking that these cheap controllers are for simple one shot machines like a Sieg or Warco X3, WM series mill or simple home built 3 axis router that just reply on 3 + 1 axis and a single spindle, often with ER collet fitting that doesn't allow pre-set tools.

You want more features, you pay your money and move up market to the 990 series controllers.