I presume you meant reseller? The normal Lexar cards are rated at about 12x. And they don't come with the IR software like the professional series (40x/80x).
The speed makes a slight difference, but anything higher up and you'll not notice it anymore. The Sandisk Ultra II is slightly faster than the Lexar by a bit, which still results in the same read/write speed on the CP5700.
The read/write speed is limited by the camera, not the CF card, just FYI. A normal card would do, like a 25x Transcend or so, but if you're choosing between the Lexar 40x and Sandisk Ultra II, based on the price, I'll select the cheaper.