Excellent support for professional volunteers

I did a 12-month placement with Cuso International in Laos, and it really was fantastic. I was especially impressed with the support from Cuso (stipend, apartment, healthcare, pre-departure training, in-country training). This is for skilled volunteers, so if you're looking to "just build a school" or "just be a body to teach English" this program isn't for you.
The selection process is super-thorough, and you'll have multiple interviews before you're called in for 5 days of pre-departure training. There's also a medical assessment you need to pass in order to be successfully selected.
Cuso provides housing with a minimum standard, but since this is an NGO don't be expecting a condo with a pool in a gated community - you'll be comfortable but you won't have luxurious digs.
Since Cuso partners with organizations on the ground, you'll essentially be an employee of Cuso, but you'll be working on a local initiative. Think of Cuso like a staffing company - for example a Cuso volunteer could be placed within an overseas Plan Canada project.
The medical support for volunteers is comprehensive, and my experience is that if you have any problems, Cuso will do whatever it can to make sure you're safe and healthy. No worries there.
The placement I was at gave me a chance to interact with Lao government office staff and adult students. The cultural experience was off the charts - I had no trouble making Lao friends and attended several weddings, a funeral, festivals, visited homes, played petang and soccer, and of course I went out to eat at tons of local restaurants.
When it comes to the Cuso in-country office staff, communication was sometimes difficult both culturally and efficiency-wise (Lao is VERY relaxed). Sometimes getting things done was much harder than it should have been, and sometimes the demands from the office were unreasonable.
But all in all it was fantastic, and I'd definitely consider another round of volunteering with Cuso.