I was shopping for a couple of new memory cards for new cameras this year and noticed that there are some SD cards that are now UHS-1 compatible. I wasn't sure what that really meant so I went looking for more info, and found that UHS stands for Ultra-High Speed and brings newer, faster signaling to SD cards.
Reading the overview at Secure Digital Wikipedia page it isn't clear if the new speeds also come with a guarantee of backwards compatibility. It seems like UHS cards might be compatible if the reader/writer also accepts SDXC cards - because they were both defined in version 3.0 of the SD spec, though the signaling (voltage and actual bit transfer) is unique for UHS cards.
Anyone with hands-on experience or links to other articles/vendor pages that might shed light on the subject?