I'm going to attempt to give some insights which might help, this is a very hard question, and some employers just read the paperwork and don't think past that, in which case my answer wouldn't apply to them.
perceived value of experience from working in a third world country
over a first world country by an employer.
Obviously this is highly variable due to individuals experience, so my answer is coming from personal observations and experience as an employer in both the Third World and First, and as a worker in both. It actually makes a HUGE difference if the employer has previously spent time in the third World, because it changes their whole outlook on expat workers. So I'll start with examining this difference.
When you work in third World you quickly notice that the majority (not all) of the expats are dysfunctional, both in their personal lives and in their working lives, many if not most of them could not hold a comparable position in their home countries (it's very common for them to hold much higher positions than their qualifications and expertise would give them back home), and some of them would be outright unemployable. A few are excellent workers with a strong work ethic, but an employer has no way of knowing which. Any references from the third World, and any qualifications are suspect.
In general dependent on the industry Third World experience has less value from a First World viewpoint for several reasons.
Validity of experience
Framework in which the experience was earned
Would be the most glaring
The advantages of employing someone with expat experience are mostly if you need someone to deal with that locality, or if you need a 'jack of all trades' type. Third World experience does often produce people who can improvise and are multiskilled, because with a small pool of skilled experts, they have to do all sorts of things that would normally be done by a specialist. For a specialist position this isn't a big asset, so a lot depends on the position.
All in all, generally third World experience would be of lesser value due to the factors outlined above and many others I won't bore you with. The most general one would be that their experience was gained in a different environment, the employer has no way of knowing exactly how close that is to their one. In terms of adherence to regulations and protocols if nothing else.
That's the guff, now here is the actual answer:-
It really comes down to a choice between known, quantifiable and relevant experience, and the unknown. Not a risk most employers would take if all else were equal.