I splurged and bought this compactflash card to use in my 7D, justifying it to myself for the few extra frames it will allow me to capture when a fleeting opportunity arises.
I have not seen anyone's test for the 32GB flavor of this card in the 7D, so:
I measured write speeds of about 53 MB/s, which is consistent with RG's measurements for the 16GB flavor of this card in the 7D.
My measurement methodology is described in this post.
I measured with a freshly-formatted (in-camera) card. I also measured when the card was nearly full, and did the speed was essentially the same.
Also, I noticed that results from my test method can vary by 5 or more percent, depending on the scene content (and hence, presumably, file size). The 53 MB/s I report is on the low side of the range I saw - the speed hit 55 MB/s in some situations, and I even saw a 57 MB/s (thought that one might be suspect).
Of course, this card is not cheap, but I think I found about the best easily-obtainable deal there is at Overstock.com, with Bing cashback. I also recommend Overstock.com because of an excellent customer service interaction I had with them in an unrelated transaction. Do be aware that they charge your credit card immediately when you place an order, though.
In my opinion, the best "value" for a big-name fast 32GB card is the Sandisk Extreme (60MB/s), which I observe to write at about 40MB/s.
