Like Biggzie said, the PLB reviews are a good place to start. I don't think, however, that there will be an all-inclusive device that will meet your needs. To be able to map your travels, you'll need a GPS that is on more-or-less constantly. The GPS units that are integrated into some PLB's are only active when the PLB is activated - this is done to conserve battery power. There are some PLB's that can accept data from an external (and superior) GPS unit. Living in Mississippi, my knowledge about avalanches is somewhat limited. The snow kind, that is - I own Chevy Avlanche! :-)

Stay safe,

JimJr