I do have some sympathy with you Emmam. As the mother of two boys whom everyone has as times found a handful, if I sense a parent of a 'calmer' child feels this is mostly down to some method of parenting that they employ - it is like a red rag to a bull. I really feel like saying 'here let's swap and see it you can do any better with these two' ...and one day I might!
However, reading through these messages I get the impression that everyone here is discussing the b/f and carrying baby ideas, not saying one or the other is right for all. As Marina says I'm sure when you're in the middle of a tantrum it has nothing much to do with how a toddler likes his milk served. In my experience, take away a forbidden toy and they cry. Offer milk ( breast or bottle) and they keep crying. Offer them the forbidden toy and they stop, as if by magic.
But in the long term, I suppose we're saying that b/f and sleeping together can have a general calming effect.
How I see it, you have an instinctive bond with your child. You just know what makes them happy and contented. (Well I like to think I do, regarding my own anyway). For some children that means sleeping with you at night and having breast feeds into toddlerdom. I think the issue is whether you choose to follow your intuitive feelings, saying boo to others, for the sake of your child. If your child feels you are in tune with them, it's a fair chance it's going to make them happier and calmer overall.
I can't hold up either of my sons as perfect models, but I have really tried hard to follow what I see as their feeding and sleeping wishes.
Both were breastfed. Older son till he was at least 10 months. I was mostly at home with him for the first 14 months, and then I was never away from him for a full week when I returned to work. He was an attention-demanding, turbo-charged little tike as a toddler.
Younger son was only breast fed for the first 6 months (happy to take bottles then). He has been with a child minder full time since. He has had to share me with a brother. Overall he has had far less cuddles and attention from me than son number 1.
Yet so far, my youngest, though not without his tantruming moments, is noticeably more self-contained and calm. He seems very sunny and contented for much of the time. Emmam, skip this bit please....He loves walking around sucking a bottle of milk (not continually, just the odd 5 minutes here and then during the day). I know it isn't brilliant for his teeth but it really makes him happy and calms him down. I'm beginning to feel the need to 'apologise' for this in public, but I won't stop till I feel he's ready. Right now, just like those who b/f toddlers, it's what I feel he wants.
As for sleeping, both of mine, older son especially, when a baby and young toddler, seem to see our bed as a soft play area. Coming into our bed wakes them up. Sometimes they want the reassurance of a cuddle after a bad dream, but my oldest actually used to emit a sight of relief when he was lifted back into his cot. I would have loved to have had him with me all night as a baby, but he just didn't seem to want it. Interestingly, my oldest get more keen on sleeping with us the older he got.