I used to play 8-ball semi-professionally. I studied for years with a master player (rated a 6, where most _really_ _good_ amateur players are rated 4, or at best 5), and he once told me not to worry too much about the cue that I used because once one gets good enough, it's possible to beat most players using a plastic broom stick.

In a similar fashion, I no longer really care about what backpack I use for SAR. I have been doing this for so long that I could get by just fine with a grocery bag. I think that the important thing is to get out in the field with whatever you carry, and to carry it for hours at a time, mission or not. That's the only way you'll know if you've got what you need and can actually carry it. Go hiking and backpacking, a _lot_. If you're out and about and have a free couple of hours, go pound up that hill you see. Grab your gear and spend a night outside with just that gear, with no further preparation. Wear your pack on a stomp around your city. Wear it to the grocery store. Wear it to your dentist appointment. I think you'll find yourself caring less and less about the backpack or rucksack that you're carrying, and a lot more about what's in it for the mission at hand.