I have two of these adapters and they work well, but they aren't really fast. Around 2 MB/sec when being used on a CSPPC, but a great replacement for hdds in my GVP HD8+, A590 and CDTV. Have used 1, 2 and 8 GB cards.
This has been my experience too. Works well, just not mad quick.
I use one in my x68000 XVI.
