Brand and label mean little. Most CF manufacturers buy the flash chips and controllers from the lowest priced vendor, slap them together, and put their label on it. I developed a test suite that exercises cards for work since we use them in embedded devices. We found that the Kingston flower cards were just fine up until a couple years ago and then they changed the controller. This changed the behavior of the card and it failed our tests. They seem to still work fine in other devices (including the MPC's).
The edge stamp (or sometime back stamp) will usually match for like cards. It's pretty common to find different sets of numbers for even the same packaged card. This just means the manufacturer changes something. One may work and the other may not.
The lesson is that "make and size" is not enough to know whether a particular card will work. You have to reference the edge stamp on the card.
We are in the process of ditching consumer CF cards. Being a consumer item they are subject to whims of the market (like being cheaply made). Sometimes I feel like I'm reliving some of the crap I went through with Zips. Industrial cards are much better and the internals rarely change, but are much more expensive. Even better is OEM'ing any type of solid state drive, then the manufacture doesn't change the design at all.
If you want to know more about CF's:
http://www.robgalbraith.com/bins/multi_ ... p?cid=6007