Does anyone have opinion on whether this is a pc or some cross? Looks a bit scop-ish to my untrained eye..

Some close up pictures of the areoles of this cacti might help potential id'ers
I think Entheogenerator was trying to link you to keeper trout and ms smiths 'pachanot'
article.

A quick Google search on pachanot will lead you to it.

good luck on this simple yet complicated question

Thanks guys, I used to have a copy of trouts notes but lost it on an old computer. After poring over lots of images I am pretty sure it's backeberg or pc, so I'm not buying it this time.
Not my photo, it's the sellers.

If that link doesn't work, Google "Pachanot". I would be willing to bet it is the first result that comes up. It goes into explicit detail on distinguishing between PC and non-PC pachanoi. If you read the whole page and study all the pictures, it should become pretty obvious whether your cactus is a pachanoi, a pachanot, or neither.

I'm either case, it's a moot point now. It's sold. But I did pick up a nice Peruvian to add to my collection today...

looks like a legit pachanoi to me. not PC.

Oops! Oh well, there are more around. I see now it does have rather fat ribs, not the telltale skinny pc ribs...
On the plus side, I saw a massive bridgesii poking over the top of a fence at a house I drive past every day. It was just glowing in the morning light. Funny how you can drive past something every day and not see it, then when youre tuned in, there it is!
I'll be knocking on their door and asking very nicely if I cam take a cut or two!