I have the  16X memorycard from interac and it worked fine, untill about a month ago I started getting save errors.  I noticed then, that the memory card was getting very warm.  So I pulled it out right away, works ok along as it is cool, but when it warms up, 15min, it get unreliable.  I am just happy I managed not to lose all my save games.  I am now the proud owner of a 251 card, no problems.
Stay away from 3rd party hardware.