Hi and welcome to tpunk !
In both regions you'll be able to travel for as little as $15/day if you're good with budgeting. And in both regions you'll have a great time.
The main difference I believe will come from the flight and the visa fees you may have to pay depending on the destinations (and on your origins of course!).
For example, Vietnam, Laos and Cambodia require visas for citizens from the USA and Canada. No visa needed for India for up to 3 months if I recall. Have a look at
this site for complete infos.
One aspect to also consider is the time of monsoon. It varies slightly between and also within countries.
Keep us updated.