For it's size and weight I'd prefer a SteriPen which kills everything...
...as long as your battery doesn't wear out. For BOB use, I would not want something that is dependant on electricity. LifeStraw for the quick drinks on the move, iodine, boiling, etc. for if you're at a fixed location or worried about viruses. Viruses are not a large concern in the US - not to be ignored, but not to be overly worried about either. Many backpacking water filters do not deal with viruses either (because for the most part, they just don't need to).