Arrived this morning, and of course first things first - benchmarking!
The results were surprising - a Class 10 card such as this should offer an average of 10MB/s write speed. The results I got on my machine - using the Disk Utility app built in to Ubuntu - were:
Minimum Read Rate: 11.2MB/s
Maximum Read Rate: 11.4MB/s
Average Read Rate: 11.3MB/s
Minimum Write Rate: 1.9MB/s
Maximum Write Rate: 8.6MB/s
Average Write Rate: 3.4MB/s
Maximum write rate occured at the very 'start' of the SD card, with the remaining 95% of the card zig-zagging in typical fashion between 6MB/s and 2MB/s write speed.
As a comparison, the Class 6 card I'm replacing with this one comes from another vendor (ByteStor) and offers lower average performance but less variation in minimum/maximum reading and writing speeds.
That said, I have tried recording full 1080i and 720p AVCHD video using my Panasonic GF2 and didn't encounter any issues. This typically requires at least a Class 6 card to avoid stuttering. Since this is the fastest I expect to be writing data to this card, it should suffice for my needs.
I look forward to seeing if other people get better benchmark results with their cards.