If it is for PSO data I will trust nothing other than a genuine Nintendo Memory Card 59. I will not go any higher because the only data I will ever store on it is PSO data. I will not store/use it for anything else incase some poor written game corrupts the data on it. I will be forever lost~~~
Having said that, if it is for something other than PSO then I like my USB memory card. It was an import (I believe made in Europe or UK...not sure exactly) that works great for saving almost anything and everything I want...then I can back it up to PC incase I ever have a data loss problem.
It is a 64megaBit (8 megaByte) memory card that has a USB port on it and software to download the information saved on it...including copy protected data that you can not back up any other way~~~like PSO data (but you would never be able to use it online because the server timestamps the data and knows if it has been tampered with or reverted to a previous save.
Like I said, I will trust none other than a genuine Memory Card 59 for PSO data...
The earlier models of the 251 had a problem with the compression algorithm and sometimes currupted save data. Many PSO players found this out the hard way.
Personally, I have many 59 cards and use 4 of them total for PSO. One HORI memory card for EP3 (we all know why)! (2 memory cards for US PSO (retired) and 2 memory cards for PSO+ (1 for challenge and 1 for level up characters)
(I have never lost (corrupted) any PSO data)
Okay, I have just about written a story here...so
Good luck and choose wisely (especially with your PSO data)
--Sheik