I've been in MP since September and it has resulted in some changes in my money management practices but I've have turned these changes to my advantage.
My auctions end every Wednesday and Thursday and we Invoice on Friday. The majority of payments are received by Sunday. MP transfers my $ early Tuesday and the $ are in my bank account Tuesday evening.
I have arranged it so all business related charges are taken from the same account
eBay uses for my payments. In my Paypal account I made my business Credit Card the default payment source so I get mileage for all Paypal expenditures such as my shipping labels.
For me MP is fine.