>Now that they've been out for awhile, what's your opinion of >XQD cards?
I like the cards enough that I have 4 of them for my D4, the one which came with the D4, which I rarely use now (16GB), a 32GB H series I bought soon after I started using the D4 because I was so impressed with them, a 32GB S series I bought when they first came out, which is the one in my D4 when I start every shoot and the XQD slot is my primary slots, and finally I just ordered a second 32GB S series today, now that B&H has them in stock again.
>How do they compare to the fastest CF card?
The Lexar 1000x cards write at 145MB/s, while the Sony Series S XQD cards write at 168MB/s. The XQD cards are also faster reading. When I'm shooting wildlife, or sports, or taking my photos off the cards into my computer the speed difference is meaningful.
>Do you see them becoming widely available for use by other Nikon >or manufacturers professional or semi pro camera bodies?
Something must be up in the world of XQD card use in the coming future. To date, Sony has been the only manufacturer in the marketplace, but now Lexar has entered the market with their XQD cards, which have just become available at select retailers. B&H has them now. I can't believe that Lexar would have come into the market if Nikon was to be the only manufacturer using these cards and the D4 was the only camera to use them. I've got to speculate more equipment using these cards will be on its way soon.