Some background about me. I'm serious about photography but don't always want to carry around a backpack full of gear. My approach with the a5100 was to replace my aps-c DSLR with it. I think I'm going to settle on still having a dslr (but a full frame one), keeping the a5100, and using them each about 50/50.
The Sony a5100 is really awesome for a compact aps-c mirrorless camera. Most of the negative reviews come from the lack of an evf or physical controls. The a6000 has those, so if that's what you want, get the a6000. I prefer the a5100 because its just small enough to fit into a pocket with most of the lenses I have. I don't find switching settings too slow without the physical controls and the screen is pretty viewable in sunlight if you crank the brightness to sunlight mode (although admittedly an evf would be awesome if it stayed small).
Anyways the dynamic range is amazing (although really only useful if you shoot raw and post process), and the high ISO noise is good compared to other aps-c cameras, although still far from the full frame competition.
The only real downside to this camera is the lens selection/prices and the autofocus is awesome on slow moving subjects but isn't as good as a dslr when it comes to sports or fast action (I don't have kids, or shoot sports too often so this is fine by me but I'd imagine that's a lot of people's concern).
For the lenses I have the 55-210mm, the 20mm pancake, the 35mm f/1.8, the 50mm f/1.8, and the kit 16-50mm. I really like prime lenses for the large aperture and the general image quality (plus Sony's image stabilization works like a charm). The 50mm f/1.8 is awesome. Great image quality at a good price. The others disappoint a little, and some of the ones I don't own and even worse that don't exist are a letdown too. The 35mm should cost a little less or be a little sharper, and I really wish there was a high quality prime in the 20-25mm (~35mm full frame equivalent) range that was essentially like the Zeiss 24mm but doesn't cost as much (I don't care if it drops the Zeiss name). Canon, Nikon, Fuji, and Olympus have this, but the $1,100 for the Zeiss is simply too much. That lens is nice but nowhere near good enough to justify the price. The main competitors charge half. It's also, unfortunately my favorite focal length, so instead I'm using the 20mm pancake, which is decent for a pancake, although I'd personally rather have a bigger lens that's sharper and with a wider aperture, and I'd pay up to $600 for it.
Unfortunately too it seems Sony if focusing more on full frame lens development--not too many releases in the last year for aps-c, so my hope isn't likely to be fulfilled unless they do another price drop on the Zeiss. Also a faster standard zoom or telephoto would be great as well.