The only difference I see is that the cheaper one is their own brand.
Be VERY careful when you order any USB dongle to get the correct coax adapters.
Those two both require MCX connectors, however, I see that they list PAL connectors as "Frequently Bought Together". That is NOT what you want for those two.
I have both E4000 and R820T dongles.
They require different adapters
They're cheap enough on ebay from China but they'll take almost three weeks for them to get to you.
Rich
For reference:
Here's the MCX to F-Type adapters
F Female Jack to MCX Male Plug RF Coaxial RF Adapter Connector | eBay
And the PAL to F-Type adapters
5X Coax CCTV PAL Male to F Type Female Convertor Adapter Connector Plug Jack | eBay