Article Summary:DPReview has posted a note announcing the release of CardBus readers for SD and MS media. "We tested the CardBus CF adapter in October of last year and were impressed, it was four times faster than a traditional PCMCIA adapter and was even faster than Firewire readers."
If you are interested in speed differences between CardBus and non-CardBus readers, check out the results of DPReview's test (CF reader comparison).
When I'm on the road, I typically carry a CardBus CF reader, an older, traditional PC Card CF reader, and an inexpensive USB 2.0 CF reader. It can't hurt to have redundancy. :)