Thanks Heiner, this is very interesting. I especially like how they have made a standard way to represent every number and how it is efficient to compare two numbers. This is not (yet) true for the system I am using. But it seems that many numbers we need to represent would be sense in this notation (like 3^^n ex I assume).
FWIW, my notation system is:
n = (c + sum(a_i * p^m_i))/d
where c,d, and all a_i are basic integers and m_i are either integers or recursively defined in the notation again. I have a little bit of standardization, but even testing equality of two numbers in this notation is not obvious. If you restrict to a single a * p^m term I think a number of problems would become easier, but Pavel has found a 2x6 TM which works not be simulatable with that simplified notation.