I've owned a Wari, they are built really well but are heavy. Found it hot in the spring when temperatures are up there.
I tried on a Snowpulse at the Snow show, they are one size fits all and it was too big for me I'm 170#, fit like a large garbage bag with cinch straps.
Tried on the new BCA Mtn Pro and it is very comfortable, incorporates the the vest technology, kill 2 birds with 1 stone.
I have a Mammut Alyeska Avalanche Protection Airbag Vest on order, bought it off Ebay for a substantial discount. Don't know how it will fit, it is a minimalist vest, only 4 liter. I don't pack a lot on my back, want it to be comfortable so I wear it often.
Wari is the cheapest although they went out of business last year.
The others with canisters are all getting up into the $1k range
All operate on compressed air which I prefer for filling reasons, $10 or less at your local scuba shop. I think the Snowpulse may be BI and can use ABS nitrogen canisters too.
Suggest you try them on, if you can, before purchasing. To me being comfortable in it is a big deal. They will all do what they are designed to do in a slide if you can get them deployed.
I'll update this with Mammut info when I get it, hopefully within a week or so.
Feel free to contact me if you have any questions, I've owned several different AVI bags.