which will receive more will vary at what satellite you are pointing at . they are almost equal ...... with the exceptions that the 4dtv won't work with the 621-2 cause it uses a diseqc switch . the 621 uses a 22k switch. So for your system use the one that works ..... some folks have their systems setup that can't add one of these without reworking the whole system, which can be a pain
i prefer the 621 , not cause its better , because right now i have a 4dtv and in the future if i run two diseqc switches and connect them with a 22 k switch to have 8 lnbs on the system. i cannot use a 22k switch if one is built into the lnbf unless i wire them seperatly. if you wire them seperatly then its like any other lnbf (no switch) corrected to say the -2 is a universal