I think everyone has used the intended terms correctly.
These recorders have both S-Video and composite inputs, but not component. The first question discussed was whether recordings made via the S-Video input actually look any better than composite. The second question was whether any existing HD component-to-S-Video converter would produce as good a result as direct S-Video input, whether that's better or worse than the available HDMI-to-S-Video converters, and whether any of these converters produces a result better than just using the lowest-common-denominator composite input.
My experience using the relatively inexpensive, and fairly expensive HDMI and component to S-Video/composite converters is, that their output is quite inferior to the native output of the source. I would suspect that a very expensive converter would be required to get an equivalent output. As always, your experience may be different from mine.
Like jjeff states “depends on the source” but when recording clean programming from a Y/C separated source like digital TV (OTA, Satellite or Cable) like you amesdp, I can see a difference between S-Video and composite. S-video usually has slightly better colours and less dot crawl.
Sometimes the difference between S-Video and composite can be minimal, while other times it's very noticeable. I always opt for S-Video whenever possible. It is NEVER worse, usually slightly better, and occasionally, much better. YMMV.