What tablet / 2-in-1 laptop should I get?

So I got an iPad 2 as a gift a couple of years ago; it's served its purpose decently, but I have several issues with it, from iTunes to the lack of a high-accuracy stylus, etc. Anyway, last year I used it mainly as a textbook / notes carrier, as well as somewhat of a calculator / simulator and web browsing device. However, because using a stylus / drawing on it was a pain (and I need to be able to do that for my notes), and because I want to be able to do some more advanced things on it, I've decided it's time for an upgrade. Right now, I'm looking at something between $500 and $1200AUD, and something that preferably runs a full copy of Windows 8.1 (not Windows RT), that way I can run specialist software. I've been looking at the Surface Pro 2, but it's so damn expensive for a 10.1" device ($100-$150 for a keyboard attachment, really?). On the lower end of the spectrum, I was interested in the ASUS Transformer, but I'm concerned it won't be powerful enough and will get annoyingly slow after a few months. --- tl;dr, looking for something like a Microsoft Surface Pro 2, but cheaper. Needs: Windows 8.1 (full) Touchscreen (no normal laptops) Screen no smaller than 10" Good stylus capability Decent power Battery life to last a day (~8 hours) Not any more expensive than a Surface Pro 2.