They are a tough one, cause on one hand we have been sending them tons of traffic for years and have always been paid on time.
On the other hand they can be very hard to deal with and easily close account , change rates and so on.
I can also add the we very lucky to have personal friends at the top of the Aff. pyramid there a while back which helped lot.
Had I been a relative new affiliate, I would promote them regardless of the “questionable” issues, PartyPoker is a great converting poker room (at least for us)