I don't really remembering favouring one over the other though do agree with your assessment gottago. The BBC was king of Saturday mornings (until SM:tv came along) but in the week the CBBC shows I remember most are the ones after 5pm, once CITV went off air.
It's easy to get nostalgic about these things, especially considering todays kids have grown up with the channels rather than the strands. It'll be interesting to see what ITV do with Thunderbirds in regards airing it on the main channel - they've given it far too big a marketing push for it to just be a CITV programme.
I preferred the internet when it had a sense of humour.