The problem with floating point comparison is not that it's nondeterministic, it's that what should be the same number may have different representations, often with different rounding behavior as well, so depending on the exact operations you use to arrive at it, it may not compare as equal, hence the need for the epsilon trick.

If all you're comparing is the result from the same operations, you _may_ be fine using equality, but you should really know that you're never getting a number from an uncontrolled source.