Well, it's never quite that clean cut, which is why there is such a difference of opinion. *Everything* has risks and benefits, and at the end of the day we all play the odds.
The new ACOG guildelines do a reasonable job of summarizing the best evidence on some of these (and completely ignore others). For example, with VBAC, the benefit is that the vast majority will have an uncomplicated vaginal birth. On average, 70% succeed in doing so, and this is including ALL women, single or double suture, supportive or non-supportive care provider, obese or healthy, etc etc. On average only about 7/1000 will experience a uterine rupture, and of those about 10-20% will result in death to the baby. So this means that a very unfortunate 10/10,000 will have a very bad outcome.
So those are the risks with VBAC -- generally small. Benefits are very good IF the VBAC is successful. Vaginal birth is better for mom and baby, avoids major surgery, baby has fewer problems, quicker recovery etc etc.
Similarly, there are risks to a repeat c-section, *especially* if mom is planning to have more than one more child. The risks with c-sections go up exponentially with each one, so 2 c/s is mildly risky, 3 is more so, and 4 is associated with a high rate of complications such as placenta acretia, increased blood loss, hysterectomy, pregnancy complications etc.
Everyone agrees that a successful VBAC is always better than a RCS. Most agree that an unsuccessful VBAC (leading to an RCS after attempted VBAC or possibly UR) is worse than simply having scheduled an RCS. But in both cases the risks are so small that it becomes more of a philosophical argument and individual decision.
Some of us highly value the experience of giving birth. Some of us feel that the advantages of having a vaginal birth are worth the possibility of failure, and that the worst likely outcome is that we end up back where we started, which is having another c-section. We know that we can stack the odds in our favor to succeed by carefully choosing a care provider, keeping ourselves healthy, educating ourselves, etc.
Other women may not know or care enough to do these things. They may only want 2 kids and they may be very afraid of labor. They may not have a complete understanding of how labor and vaginal birth benefit a baby. They may be subjected to scare tactics and provider bias.
At the end of the day, we all choose what we think is best. I feel like it is my job as a woman to provide other women with accurate information about their options, and the relative risks and benefits of each option. But at the end of the day, I can't change someone's mind and I don't really try to. I have 3 acquaintences who all had c-sections with their first, and were all "planning" VBACs with their second, though they weren't particularly adamant about it. They went back to the same doctor and hospital with baby 2 as they did with baby 1. They didn't do their homework, they figured they'd give it a shot within the terms that their not-so-VBAC-friendly OBs set. Two of them had CBACs and one had a VBAC despite the odds. They were all fine with the outcome, and they didn't feel "wedded" to the idea like some of us do.
Most women you will find here do feel quite strongly about having a fair shot at a VBAC, and I believe as a board we have a pretty high success rate (though I couldn't tell you what it was -- there is certainly some sampling bias here). So just know that you have a friendly place to come, where we don't think you're crazy here. Your local ICAN group will be another good online and in person place to work through some of the issues that may come up for you during this pregnancy.
Best of luck!