I want to get a smart phone in Thailand.

Not interested in Iphone...

Only android phones.

What kind of phone would work in Canada and Asia?

I'm looking at Imobile, AIS and Samsung? But open to recommendations.

I've head that all smart phones are not the same and the quality can vary greatly?

Cheers!

I also don't know a lot about smartphones, technically. I bought a Google Nexus 5 ONLY because it was advertised as worldwide unlocked. I've been happy with it, but then I was happy with my Motorola.

Let's start by separating a few things out.

iMobile is a phone brand, Samsung is a phone brand. AIS is a network that will be badging phones.

Herein lies the answer to your question. If you buy a phone through a network there is a chance that it will be "locked" to the network. These phones can be "unlocked" by yourself or by paying somebody to do it.

No, all smart phones are not the same and quality at the lower end can vary greatly.

ASUS, LG and Lenovo (I might have missed) some have great phones at the lower end of the scale. The ASUS Zenfone 5 (I have one) has really shaken up the bottom end of the market with a mixture of good tech, good build quality and sensible custom user interface (note I said good....excellent for the money though). If you buy a phone the is network free then your only concern is network bands. I believe that Canada and the US operate slightly different frequency GSM networks to the rest of the world but I don't think that has much effect. The only other concern is 3G/4G. The difference here is mobile internet speed. 3G is fast enough for most mobile applications and 4G is geographically limited anyway (and not a concern in Thailand).

The bonus for you as a user of an ASUS Zenfone 5 will be that it has a dual SIM capability allowing you to have a Canadian SIM and a Thai SIM in the phone always. This is not true of the LTE (4G) version. Stick to the 3G version and you will be "quids in"!

Here you go. More information about bands - http://en.wikipedia.org/wiki/GSM_frequency_bands#GSM_frequency_usage_around_the_world

Most phones available now are Quad Band. The Zenfone 5 is.

I am a merchant seaman & use my phone everywhere. What you need to look for is a quad band/gsm. I use a samsung. Recomend dual sim card. Bought it straight from a samsung store so it was unlocked. Hope that helps

One other thing. Get as much memory as can afford

What network in Canada? What network in Thailand?