My obstetrician has always maintained that the riskiest way for a baby to be born is by means of a forceps delivery. Outlet forceps are not always bad (by that time it is too late for a CS anyway), but she has always told me that as a doctor she would never agree to mid-high or high forceps. These include the dreaded Kiellands forceps of course, but also the Neville Barnes and Simpson's forceps.
I am not entirely convinced by the argument that it is sometimes too late for a CS. Of course if the baby if crowning or the head is already out it is certainly too late! I just keep thinking that if forceps fail ( as they often do ) then they move to a CS. By that logic they could have moved straight to a CS, couldn't they? If anything it would save time and the possibility of having mum recover form both a forceps birth and a major surgery.
My advice to you is to not go by what anyone here is saying because a lot of us will have biased opinions based on our own experiences.
I've looked up some research for you and hopefully this will help you to decide which risks are preferable to you.
www.thieme-connect.com/ejournals/abstract/ajp/doi/10.1055/s-2003-42775
(states that forceps are known to cause brachial plexus nerve damage)
journals.lww.com/greenjournal/Abstract/1984/06000/Birth_Trauma__Incidence_and_Predisposing_Factors.7.aspx
(Logistic regression analysis of fetal, maternal, and intrapartum complications in labor and delivery revealed that midforceps, shoulder dystocia, low forceps, infants greater than 3500 g, and second stage labor exceeding 60 minutes were the predominant events associated with fetal injury)
journals.lww.com/plasreconsurg/abstract/1990/01000/facial_nerve_palsy_in_the_newborn__incidence_and.1.aspx
(states that facial nerve palsy is most common in macrosomic infants or those born with the aid of forceps)
facm.unjbg.edu.pe/revistaspediatria/Clinical%20Pediatrics/2004/Pediatric%20Clinic_51_June2004_%20the%20Newborn%20Nursery%20Part%20II/Management%20of%20birth%20injuries.pdf
^ Fabulous article about birth injuries. From what I could make out majority of the birth injuries had forceps listed as the major risk factor, other than of course fetal birth weight of more than 3500g.
www.sciencedirect.com/science/article/pii/0029784496001512
(lists forceps as a major risk factor for pelvic organ prolapse)
www.sciencedirect.com/science/article/pii/S0002937803005726
(there is an increased risk of anal sphincter damage and hence incontinence with a forceps delivery)
www.bmj.com/content/308/6933/887.abstract
(lists forceps as one of the major risk factors for third degree tears)
I can't imagine why anybody would prefer a forceps delivery over a CS, but I respect that everyone has a different way of looking at risks and benefits. If you were to ask me personally, I'd sue for assault if forceps of any kind were brought within one mile of me. Nothing has the potential to upset me as much as a forceps delivery when it comes to childbirth, particularly when it is forced. 