I've been using a Sony NEX-7 mirrorless camera since March. It's received extensive use, and has loggged over 8,000 images on it. I haven't touched my Canon 5D II in weeks, except to do some portraits with it the end of April.
I've accumulated an assortment of lenses, lens adapters, and accessories for the NEX-7. I find I'm doing most of my shooting at this point with prime lenses manufactured by Voigtlander for m-mount cameras. Several manufactureres make m-mount adapters for the NEX-7, and I own two of them.
I continue to reach for the Sony instead of the Canon for one reason: it's so light weight. I ususally don't even use a neck strap. I got a wrist strap for security, and just carry the camera around in my right hand. I can do this all day. This is a camera that seems to be made for hand-held shooting, though I've also used it on a tripod. The light weight, combined with the absence of "mirror slap", means I can shoot sharp pictures hand held at relatively slow shutter speeds even if the lens doesn't give me image stabilization. When I use a stabilized lens made by Sony, it does its job well and, again, because the combination of camera with lens is so light, I can shoot hand held down to a quarter of a second without blurring the image.
A couple of months ago I got the 30mm macro lens that Sony makes for this camera. But it only opens to f/3.5 and I'd say it's only mediocre optically, though still a decent value for the price. For lower light and shallower depth of field I got some extension tubes make by Kenko for the e-mount camera. I mount the extension tube on the NEX-7 body, then mount the lens on top of it. If I want to use one of my m-mount lenses with it, I put an e-mount to m-mount adapter between the extension tube and the lens. I've been delighted with the way this combination works.
Here are three images from the NEX-7 shot with a Voigtlander 50mm lens at f/1.4, with a 10mm Kenko extension tube attached. I took them around the garden at my house. My wife takes credit for the green thumb.