What would be the significant differences between these two on my system? I am running an [email protected] GHZ,2 GB RAM and a HD3870. I have a free PCIe slot and am very capable of installing it but I can get the USB version for the same price and it seems to better suite me atm for ease of use of the inputs and whatnot. I don't really plan on recording any OTA HD material(I may though),I just want to backup all my shows from my set-top DVR. Any input on issues/PQ between the two? Thanks.