I got a pair of Inov-8 Roclite 295s about two years ago for trail running. The model number comes from the weight: 295 g each, which is fairly light. They're great for trail running with good traction and work well enough for USPSA. But I'm not convinced that the lightweight design is the best option for being on your feet for hours on end.
I've used the merrell trail gloves, nb minimus, and now the vivobarefoot neos. all of them are minimalist type shoes that weigh even less. All of them were super comfortable for being on my feet all day. This despite the conventional wisdom that a tubby bastard like myself would need more cushioning.
Fit probably matters more than weight.