Am planning on Vietnam with a 1 year old but keep changing my mind! Starting to get immunizations, but still getting cold feet! Would stay in nice places and limit internal travel, but some people keep putting us off!
I went to china with ds1 when he was 15 months old. Found it to be not very child friendly to be honest although this did not spoil our holiday. Things that we struggled with were driving standards particularly in taxis are hair raising and no child seats will be provided. the standard/availabiliy of cots in hotels (absolutely awful even in some well known international hotel chains), the lack of high chairs in restaurants/hotels - we had a booster seat with a tray with us which we hauled everywhere but which was a life saver as could not get ds1 to sit still long enough to eat without it.
Also we found that the local chinese were very interested in european babies and were always wanting to take his photo - not all of them asked first just pointing a mobile phone at him as they walked past.
Having said all this we had a great time and coped well - just thought i would let you know the problems we had.
We went to Brazil when DS was 13 months and had a great time. Absolutely loved it. The main problem we had was that DS did not approve of the local food and the only ready made food available locally were purees for 4-month-olds (we were on a small island). So he survived on those and bananas. The other issue was that it was impossible to get him to sit still in a restaurant so eating out was an issue.
Took him to Thailand when he was 2.5 and that was less easy but I think it was just a function of the terrible twos - dealing with a full on tantrum is not fun on Phi Phi or in Tesco, Surrey Queys.
I would say you have to lower your expectations with regards to facilities and be relaxed about routines but apart from that both trips were really enjoyable.
DD was born in China and we lived there until she was about 11 months old. Annieshaf speaks the truth.
Have been to Vietnam but not with a baby, and the standard of driving is even worse in Vietnam than in China.
Depends how precious you are about things like car seats. Living there, I just had to grin and bear it, and do the few little things I could to moderate the risk (i.e. not travel on motorways, where the cars are travelling much faster).
I've no experience of South America, but I've travelled extensively in the far east with DC since they were toddlers. Do it now (while they're still portable and biddable!!! - gosh sounds like a dog) it's so much more difficult to impose your will upon them (re visiting places like temples, palaces and interesting restaurants etc) when they are stroppy teenagers!
My advice is travel light (clothes for DC are very cheap in far east), buy sealed bottled water from reputable sellers, take your own baby mozzie nets, take loads of Avon skin so soft woodland spray oil to protect DC against mozzies and expect the unexpected!