My current sd card on my HTC EVO running out of space with all the video, music and themes..etc. My local staples has sale on Sandisk sd cards. 16gb card for $19.99 and normally sells for $60. Its says class 6 on staples website, but on Sandisk it shows all the Ultra cards are class 10 except 4gb size. My question is regarding the class rating. My Google research today and here on Phandroid. Most sites say the 10 class rating for HD videos. My current 8gb card came with evo was a 4 class rating. Is anything more to consider far as the rating. I realize not going to speed up phone, like night and day difference. Just trying to learn here. Sounds like a good deal and class 4 is only two dollars cheaper and not Sandisk Ultra either.