which parser to use

[a_nuther at geek.org]

I'm building something that requires parsing a rather complex
language. I'd like to do the whole application, including the
lex/parse phase, in Python (for development/debug speed), and only
move parts of it to a compiled language if execution speed absolutely
dictates. So, what i'm looking for in a Python parser is:

    1) reliability (don't want to debug a parser)
    1) flexibility (i do a lot of refactoring)
    2) E/BNF friendliness (working from a spec)
    3) speed (moderate speed will do; glacial won't)

Does anyone have any familiarity with some of the several Python
parsers out there? Any pointers to comparisons (as opposed to surveys)
of _several_ of the Python parsers would be much appereciated. (I've
seen the YAPPS/Spark comparison.) If none of the Python parsers really
fit the bill, any thoughts on ANTLR, Spirit, etc?

Thanks in advance,
E