I'm recording freesat from a Foxsat HD box into an EX77 via RGB scart. It records at SD resolution only, but the far superior bitrate of the HD broadcasts still show through in better colours and less artefacts: HD stuff looks as good as standard DVD when recorded in XP mode (and even, at a push, in SP mode). This is very noticeable when you are upscaling back onto a full HD display: the downscaled HD stuff scales back up better than the "always" SD stuff.
Example: the KD Lang concert on BBC HD at the weekend: the copy on my hard disk is as good quality as any DVD I've seen.
HTH