I don't have my GBA with me... but I thought a good benchmark to do would be to take a large ROM...something like Mario Pinball and note the times that it takes to load when both compressed and uncompressed via the supercard.....so that we can compare though we should always use the same game rom.
So for example:
CF Brand - Sandisk 512KB standard
Comp Load - 25.5 seconds
UnComp Load - 10.4 seconds
comments/Issues?....
CF Brand - Kingston Hi Speed 1GB
Comp Load - 19.5 seconds
UnComp Load - 6 seconds
comments/Issues? slowdown on game from compressed rom.
....anyway you get the idea....

Is it worthwhile doing this?