Non-direct linking schemes advantages?

[Alfa]

Hi everybody,
When I was surfing and looking for new hard link exchanges I find the following linking scheme
site A(PR4) -> site B (PR4) ->site C (PR?)

is more prefered by the owner of 'site B' then direct link exchange A<->B

How do you think guys what is advandates of such linking (if I understand PR formula well - there shoudn't be any difference for B). So where is a catch?

Alfa

[Bill]

Well, in theory pure recip links are devalued by google.

And 'one way' or non recip links are seen as more natural, and therefore as likely to have more value.

In practice, a mix of recip and non recip is probably optimum. The question is, what number of each is ideal? Since recip links are traditional and still a standard in many situations, that makes each non-recip link particularly valuable, to balance out all the other recip links.