lilyaldrin: there is a significant difference in rear facing car seats indeed. But since cost seams to be what most people complain about regarding ERF seats, that is why I only mentioned the affordable range.
I do however always recommend buying Extended Rear Facing car seats that are PLUS tested approved. As you can not get any safer. Those are seats that have undergone the viorous swedish PLUS test which measures the strain on the neck. No forward facing car seat will ever pass this test (yes they have measured), and not all rear facing car seats do either, though this is a test that costs quite a bit, so not all manufacturers send a seat to have it done.
A short description of all the tests a car seat can go through:
www.carseat.co.uk/Child-car-seat-safety-tests/Explaining-tests-and-approvals
Explanation of the PLUS test:
"Child restraint systems, Plus Test
The Plus Test is a voluntary test, inheriting thoughts about important protection of head and neck from an older national child restraint approval. In a Plus Test, the forces subjected to a child's neck in a frontal collision are measured. The Plus Test is an additional test carried out on seats designed for the Swedish market. This form of testing is not conducted anywhere else in Europe and is not included in an E-approval. An E-approved child restraint system meets all the statutory requirements for sale in Sweden, but a seat that has passed the Plus Test gives the child additional safety. A seat that has passed the Plus Test is E-approved for installation in every seat row in a car. Such seats ensure that child passengers are not subjected to life-threatening high neck forces in a frontal collision.
The Plus Test has been developed through collaboration between VTI, NTF (Swedish National Society for Road Safety), Folksam, SIS (Swedish Standards Institute), Volvo and representatives of manufacturers of child restraint systems."
www.vti.se/en/vti-offers/crash-safety-testing/child-car-seats/