Barbell bent over row form

[coalminer]

I was checking various web sites for proper form on barbell rows and saw recommendations to pull to everywhere from the upper waist to the chest, and the bent over position from 90 to slightly lower than 45 degrees.

I'm pretty sure that the bent over degree will affect trap and delt involvement, how does the position pulling to affect the lift?

Are there any injury concerns with the different positions?