I ended up getting one of these (John Lewis price-matched the Currys deal, so I got the higher end machine with the keyboard cover for £525) because everything I was reading about the Surface Pro 4 made it look like it was heading towards a Intel M processor, which for my use wasn't enough of an improvement over the Cherrytrail to warrant the price difference. Looking at a lot of benchmarks, the S3 isn't much outperformed by the i3 variant of the S3Pro, mostly due to thermal throttling constraints, and performance wise I've no complaints so far.
I needed a new machine as my ASUS S2000, had died. The ASUS UX305 was top of my hit list but I'd read there were a lot of issues with the intel video driver that hadn't been resolved, so it put me off. In the end, after looking at various other bits of kit (Toshiba Click Mini, Transformer Chi, Dell Chrombooks), I opted for the S3 and have to say I'm pleased with it.
It's not cheap but it's not Apple expensive either. it's surprisingly difficult to get a high res screen on anything this small, which is also a limiting factor. Far too many of the smaller screened devices feature x768 as part of the res, which in this day and age is naughty.