I purchased a Katana 32MB memory card and wireless controller last weekend. I must say it's excellent quality. No issues whatsoever. I'd say it's as good as or better than the Sony made stuff (for the price anyway). You can't beat officially licensed peripherals.
16MB worth of elf files = WIN
I've used both generations of Logitech wireless controllers. The first generation felt a bit more sturdy, but I wasn't really impressed with them. The second generation seems decent, but both sets ended up with sticky buttons before long.
Xbox 360 Elite - Virgin
v7 PS2 - CC2.0 w/ 4MB Flash & 320GB Seagate HDD
v1.4 Xbox - Soft-modded and TSOP Flashed
Model 2 Sega Saturn - MPEG Video Card & Modded w/ Racketboy Chip
Dreamcast - Revision 1 [CD-R Compatible]
XBox Live Gamertag: TheGMan3825