well, we have never had ANY problems with passport hardware. It can be something else, you have written "weird problems" but nothing more... what problems exactly? Have you tried to find out what is going on pp8600? 3com's 8800 have other problems, but it is relatively new switch. Passport's TX and TXE cards are quite old but still these cards we have are working really fine in four pp8600 we have deployed in our core network few years ago...
Brat