Almost every DVB-S and DVB-T tuner will record the MPEG2 (or H264 for DVB-S HD) compressed video exactly as broadcast by the broadcaster - as they compress the video at their end. (No mainstream tuner card re-encodes digital broadcasts - they just receive the encoded video as broadcast)
Therefore the picture quality and resolution (and file size of recorded shows) are entirely dictated by the producer (though the end user can alter the quality of the decoded image by codec choice this is independent of the tuner card)
For example a recording of BBC One on Freeview in London made in Vista Media Center should be identical in quality which ever tuner card you use - the only differences may be in borderline signal-strength/quality areas where more sensitive tuners may get an error-free signal in cases where less sensitive tuners won't.
For info :
BBC One, Two, Three/CBBC, Four/CBeebies and News 24 are 720x576 on Freeview and DSat, with 301, 302 and BBC Parliament 544x576 on Freeview (not sure about DSat)
ITV1, C4 and Five are 704x576 (or 720x576 - can't remember) on Freeview - but on DSat ITV1 and C4 are 544x576 (to save bandwith to squeeze more regional variations in)
Most of the ITV2-4 and +1 variants are 544x576 on DSat and Freeview (apart from the Freeview ones broadcast on muxes other than Mux 2 - the main ITV/C4 mux)