Nigel, we use both clubs and I think it's 6 of one and half a dozen of the other. Arrivng late at a CC site at busy times you will have very little choice anyway, and only the least attractive pitches will be left. We have used a lot of C&CC sites and have always had a satsfactory experience. It's true that they are often quite specific about how they would like you to pitch on the contiguous grass areas, but that is invariably to maintain separation and of course it also prevents your neighbours getting too close to you. We have an "odd" outfit (door on the wrong side, awning makes us wider than we are long) and we have often arranged to pitch sideways on or the opposite way round - we have never been refused a sensible request.
Even CC sites will sometimes have to organise pitch allocation where there are different sized pitches, or they will reserve hardstandings for motorhomes when the grass pitches are soft (as we experienced at Blackmore CC).
We have recently used Lower Wensleydale CC, where the many of the pitches are very small - we didn't have a problem, but a bit of allocation would actually have been helpful; all but one of the small number of large hardstandings were occupied by solitary motorhomes, with no car or awning to accommodate, while some caravanners with awnings were really struggling to find big enough pitches - but that's how it goes.
Last week at Ravenglass C&CC, where many of the pitches are small and oddly shaped, we were allocated a pitch - it was clear when we sited the 'van that we would be not able to pitch our Khyam awning without the guy lines being very close to a footpath, and we were offered two alternatives without any fuss. The empty pitch we would have chosen was kept back for a 26' caravan, which was fair enough - the wardens were doing their level best to make it all work, and were very pleasant and helpful.
Both systems work, and we have rarely been unhappy with a pitch - in fact, the worst I can recall was actually at Blackmore CC. We had to take one of the last three very sloping grass pitches next to the roadway, where not one but two other members thought we would like to watch them stop and empty their dogs as they walked by - not something I want to see when I'm sitting out eating, nor the bagging up operation which they seemed to think made it OK!