I think for both routes (CS vs. vaginal) there are short and long-term risks and benefits. Which is why I think it makes sense that each woman should be able to decide for herself how much she's happy with either set of risks.
I think for long-term risks/benefits, this new meta-analysis might be the best (even though they lumped all kinds of caesareans together and didn't control for maternal factors that led to the Caesarean in the first place):
journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002494#sec023 [Keag et al., 2018, Plos medicine]. Particularly see their table S7 for % increases/decreases with CS vs. vaginal.
Basically what they report is: risk of later developing urinary incontinence or pelvic organ prolapse is reduced with CS (-10% together - and this is only comparing CS to normal vaginal birth, not to instrumental birth, which is worse). But risk is increased in subsequent pregnancy for miscarriage (+1.4%), placental problems (+0.5%), still birth (+0.1%) or hysterectomy (+0.1%). [And there is also other studies that show that the placental risks increase with each CS] And for the child: reduced risk of inflammatory bowel diseases (-0.1%), increased risk of asthma (+0.6%) and obesity (+3.6%).
For example, for me personally, I was pretty concerned about the pelvic floor problems and given my weight, I think that obesity won't be a problem and I only want one more child, so the set of risks with planned CS seemed preferable.
And in any case, if you decide to give birth in a hospital (rather than in midwifery unity), at 30, the risk of ending up with a CS or instrumental (forceps or ventouse) is ~45% [see bmjopen.bmj.com/content/4/1/e004026.short , Li et al., BMJ open, 2014, table 3]. And both of these have worse outcomes for the baby than planned CS.
So, basically many things to take into account, which is why to me it makes sense that NICE guidelines say that it should be up to the woman after getting all the information.