I bought the EVAC-U8 smoke hood because of a few things

1. It packs small ( slightly (30%) larger than a can of coke )
2. It filters out most chemicals found in smoke including carbon monoxide ( which is the most lethal gas in the bunch and the cause of most smoke inhalation deaths )
3. It's relative lower cost

It is not to be used in a low oxygen environment ( <15% i think ) and should not be used as a gas mask if there is a chem/bio attack.

The others I've considered either don't filter out carbon monoxide, come in a large pack or are just too darned expensive.

Jsut my thoughts.