The most important thing is that you know how to use what ever one you buy!!
I have a piepes and LOVE it. Simple to use. # antenna instead of just 2 (like most beacons). makes for faster searches.
I have a tracker and an SOS. I like them both. Have to agree with Rixster--knowing how to use the one you have is the most important.
Take a avy class and practive often with your buds out on the snow.
Purchasing the equipment is only 1/2 the equation.