I've just covered this in antenatal classes as well. The green NHS notes seem to really push having the injection and before my class, I'd just assumed I had to have an injection after baby was born. Now, I'm thinking I'd like to try and get the placenta out naturally and maybe go for the injection if it seems to be taking a long time. I definitely want to try and do delayed cord clamping.
As for eating placenta and capsules, that's not for me!
My mum had the injection with all 3 of us. Apparently she managed to fire the placenta out with such force on one occasion that it hit the consultant square in the chest!! My mum said he had unusually large hands and it was payback for the internal examinations!