I got the c shape nursing pillow and have used it loads with DS1. I used it for breastfeeding and I found that he would sleep on there (supervised of course) and that was the only place he would sleep if he was not held.
I also used it for tummy time for DS1 and when he was sitting up, I put it in front of him when he was sitting in the corner of the corner sofa and I put toys in front of him so he could reach them and when he was sitting on the floor I put it behind him so when he fell he would fall on the nursing pillow. Before DS1 was born I used it whilst pregnant as support on my back.
I have used it whilst breastfeeding DS2 and I will use as outlined above with him.
Although it can be seen as a waste of money if you use it loads then it's great value for money.
I got the one from the bounty pack vouchers it's not hard and it's not soft. My sis in law got a pink one maybe from mothercare or toys r us and I thought it was too firm and I honestly did not see her use it much.
I have used it for a lot of things and I think it's great.
I know somebody who used it for breastfeeding and she had a c section and she said it helped in covering her stitches so baby did not hit her stitches.
Keep us updated whether you got one and whether you think it's useful