Ok to give you some perspective...

16Gb SanDisk Ultra 30Mb/s - Write 23.7MB/s Read 39.4 MB/s (£39.99)
4Gb SanDisk Extreme III 30MB/s - Write 28.9 MB/s Read 28.9 MB/s
16Gb Transcend 133x (cheapo backup card) - Write 12.0 MB/s Read 25MB/s (£17.99)
16Gb Duracell Pro Photo 300x UDMA - Write 15.6 MB/s Read 42.3MB/s (£20.99)

All tests with the same software but on a SanDisk Extreme Firewire 800 reader.

So my tests pretty much show me the same thing as yours did, the SanDisk cards win hands down for speed, but for value for money I am not so sure. Duracell do a 600x of that card for £27.99 so I might give that a go!

It certainly seems that in terms of speed, Compact Flash still has the edge.

Edit - Just for the laugh I did the same test on my Drobo, Write 4.9 MB/s Read 6.7 MB/s. I'd be interested to see the results from anyone else with a Drobo, as I have always thought mine was faulty!

Cheers

Cris