The Eco wool cardigan that I am knitting has a big collar, knitted separately rather like a sailor collar, and sewn on afterwards. The instructions are for two versions, one in bramble (or blackberry) stitch and the other in garter stitch with the yarn doubled. Given my opinion of garter stitch, knitting a collar in over-size garter stitch would be like saying I'M NOT VERY GOOD AT KNITTING, so that's out. I started knitting the blackberry stitch collar, but the slightly fuzzy yarn combined with the variations in colour meant that the texture of the stitch wasn't apparent. After knitting about an inch, it was starting to look a bit like lumpy porridge - not a good look for a collar (or even for porridge). So I switched to moss stitch, to match the cuffs, button band, etc. and that is looking much better.
The first attempt at the collar, following the pattern, was also ridiculously wide. The instructions don't say how wide it should be, but from the photo, it appears to be wider than the shoulders of the model. That's much too wide, I think, so I have reduced it by about 25%. I have started stitching the body of the cardigan together, so that I can see how long the collar ought to be - it's looking good.
(later) It's finished! All I have to do now is finish sewing the whole thing together.