I got my first pair of trail shoes via Brooksrunning.com and have managed to put about 100 miles on them so far.
The PureGrit2 ($110) weighs 8.2 oz for ladies', and 10 oz for the men's shoes. This is considerably lighter than many trail shoes on the market, but slightly heavier than the original PureGrit.
And they feel light...weighing less than my usual road trainers by an ounce. (Weight makes a big difference, especially in racing if you encounter water, as anyone who has ever ran in very wet shoes knows!).
These are part of Brooks Pure line and are designed with a 4mm heel-toe drop. There is good arch support within them, but they still maintain a "natural" feel. The asymmetrical lacing feels comfortable, and once laced, I don't notice them again.
Compared with Brooks Cascadia8, these are a sleeker, nimbler model. The Cascadias feel more like a rugged hiking/running shoe with a wider toe box (too wide for my foot), but the PureGrits fit more closely with less sole and bulk to the upper.
How they performed
I was able to test the PureGrit2 shoes on a variety of trail surfaces: gravel, bark, grass, packed dirt and slick mud. Unfortunately (or maybe fortunately), I was unable to test them in loose sand, snow or icy surfaces.
The hardest test for the shoes was certainly mud, but in my 7 mile run with mud I lost traction only twice- both times going downhill on a very slick slope, and only momentarily. Overall, they handled very well on each trail they were worn.
The flexibility rivals my other speed shoes, but they are still sturdy and protective. And as far as protection goes, there were no issues with rocks poking through to my feet. I suspect there is something (thin plastic maybe?) within the bottom of the shoe to prevent this.
The PureGrit2s seem to almost repel mud.
Water penetrated my PureGrit2s when going through puddles, but the mesh upper fabric design allowed for it to drain quickly. My friend, who wore regular trainers on the same muddy run, had mud caked on her shoes when we finished.
A couple of cautions
The heel tab/achilles notch hits my foot a little higher than in some other shoes. Wearing longer socks will keep them from rubbing sand or dirt into your foot. Gaiters are also recommended for especially gnarly trails.
If you are new to the 4mm platform, take your time adjusting to them.
The PureGrit2 are an excellent lightweight trail training and racing shoe. I would strongly recommend them to anyone, especially those interested in a trail shoe with lots of flexibility and a lower heel drop.