Well, for transferring from PC to Amiga they're a great idea. In fact you might be able to get a PCMCIA adaptor for the A600 to use compact flash cards (you might not need another IDE port).
I'm just wondering why people pick the compact flash card though and not SmartMedia, SD, XD or Memory Stick. Is it due to Aminet drivers?
Another advantage of solid state is that they don't need that much juice. A heavily expanded desktop unit could have trouble with external scandoublers, accelerators
and a motorised hard disk - particularly when a PPC/BVision comes into things. They won't get bearing failure or overheat either.
Right now my Simpletech 1GB 2.5" (A1200 IDE) flash disk is reporting a SysInfo 'SPEED in BYTES/SEC: 1,077,304'. Not sure whether Fast File System slows down this benchmark but I have noticed the speed results lower as the drive fills up.

A Quantum Fireball 2GB 3.5" (SCSI-IV - ASynch) hard disk is reporting a SysInfo 'SPEED in BYTES/SEC: 3,419,269'. For multimedia or general DOpus file management this 3½ increase is very noticeable.
For main system use I found the 2MB/S rate of a 2.5" hard disk pretty slow so half this again and you can see a definite niche area of use for a flash drive.
The Amiga could make good use of such a drive but can you imagine using a Linux swapfile or Windows virtual memory on something this speed? You'd pull your hair out!
EDIT:
After reading the
SSD Buyer's Guide I'm puzzled why I'm only getting 1MB/S. Maybe it's something to do with PIO Mode-0/1/2 or Mask/MaxTransfer.