Which degree carries more value, in the world of research: Biomedical sciences or Biochemistry?

I guess it depends on the type of research you are interested in. I am technician in a large cancer research institute, most of the students have degrees in biochemistry or biological sciences from good unis so pick your institution carefully. A degree with some type of placement will give you an advantage too.

From which degree would you have a better chance of getting a job? which pays better?

I only know about academic technical posts. most ask for a a "relevant degree" so i don't think the subject will make much difference to pay. A broad biological sciences degree would cover the most areas. I suggest you check out the recruitment pages of unis, hospitals and biotechs to see what they are looking for.

I don't think that it really matters- more important will be the reputation of your supervisor, the publications you get out of your PhD and the actual subject of your PhD. If an employer is looking for someone with a specific profile they will not be bothered about the type of degree.

Many students doing a Biochemistry degree don't actually do biochemistry, they might be doing more cell biology or molecular biology but recieve a degree in biochemistry because that is the degree the department gives all students by default.