renosteinke,
The whole idea of the lithium batteries is to reduce weight. With Milwaukee's 28v you're supposed to get 28v of power in a 18v weight class. They're far too expensive for my taste but more than a few guys buy them for "bragging rights" and they could certainly be useful in some situations.
I've subscribed to CR for many years now and by and large I think they do a good job. I'm less sure about tool reviews because I think their audience is weekend warriors not contractors and the tests may reflect less demanding work. With that said, if they test a dozen drills the same way and one fails, it says something about the quality of that drill.