If weight is the most important aspect of a filter, then maybe this one is for you. But that isn't without sacrifice...
Backflushing it often gets tiresome. When your tired, and the water is cold, you really aren't going to want to spend your time with the backflushing routine.
The cartridges are small, and need to be replaced more often. Also, always carry a spare cartridge on any long trips. It will get to the point that it almost wont flow through the old cartridge even if backflushed regularly.
I wouldn't buy this unit again and I wouldn't recommend it to a friend. But, I can see how it's inconveniences could be worth it for the weight conscious.