I own no rugs with necks - and in winter my pony is fully clipped. I'd challenge anyone to find a neck rug that would fit round Murphy's neck!! He doesn't need one though, he has 3ft of mane to keep his neck warm
I have a couple of fleece's with a neck, and then a h/w horsewear rhino with neck for the pony. I can fold the necks back on all of them which I do more often than not. All my other rugs have the option for necks and I have two neck rugs (one for each) which I'll stick on when the weather is really bad mid winter but other than that much prefer not using them.
Of all the rugs I have for my 5 horses, I only have one H/W turnout rug with a neck, which my 28yo wears mid winter. However, even that wouldn't have had a neck if I'd have been paying full price for the rug - but the rug at the time I bought it was such a bargain that the fact it had a neck was immaterial.
Oh and like Enfys, I don't possess a stable rug either (love the icy photo Enfys). I did have one once, but it got "moused" and has never been replaced.
Mine have a rug for every occassion, I'm a rug-a-holic! All stables have half necks and turnouts all have detachable necks. Never found they've rubbed manes, if anything they've encouraged mane to lie nice and flat, Spose depends on make and sizing.
I have a 6ft9 weatherbeeta something turn out rug with a neck, because it came with my 17.1hh TB! I am 5ft2, can you imagine what a pain in the butt it is trying to put that on! It doesn't get used much!