Yes, the Our Generation dolls are cheaper, but they are also lesser quality.
For most, it isn't an issue but the hair, because of the lesser quality, doesn't stay as nice, and the vinyl is not the same quality. That said, they are very nice play dolls, especially for children who don't take care of things (which is the majority at a young age).
Gotz dolls, like Hannah and Happy Kidz cost as much as AG, but they are easy to get in the UK and difficult to get in the USA. I feel, that quality-wise, Gotz wins over all the other play dolls of that size. Sadly, they stopped making Kidz 'n Catz dolls so can only find them at secondary seller places.
Maru and Friends are beautiful and well made, but 20" tall so it's harder to get clothes, unless you can sew, as I don't know if Our Generation or AG doll clothing will fit.
I liked it years ago when there were so many makers of dolls and all were so different, yet the same size and could share clothes.