which do you think is the best for developers

[colditz]

hi!
i'd like add a couple of new features in a gnutella client. i've been researching for limewire but in my opinion there is no a full information (or i haven't foud it) about how limewire works.
which is, in your opinion as developers, the best client to chose to develop features by for example documentation, simplicity... other thinks

thanks everyone