Is it too big to be used as a tablet? Has it replaced iPad or Android for you?

Replaced my 3rd gen ipad. I used to prop by iPad up anyway when watching movies or doing certain apps and this is a lot more powerful. I also got rid of my MacAir that I used for 2 years. No question it is good as tablet as well.
 
I vastly prefer something with a proper kickstand that can be propped up at any angle (except upside down, or diagonally balanced on a corner), to a lighter device that I always have to hold. With the surface, you can even watch it oriented with your head while lying on your side (if your mattress is firm enough that it isn't too slanted) if you set the typecover and kickstand to form a sort of tripod (with the screen as the third leg). When I'm sitting, I still want to put my tablet in my lap, so the kickstand of the SP3, or an older surface with a FreedomCase makes that more comfortable. My iPad Air is still too big to actually be comfortable held in one hand like a book, so it's actually less comfortable; I can't make it prop itself up except in a couple flimsy positions with the smart cover; sideways never works. So while my Surface can't replace my Kindle Paperwhite (ignoring the huge difference in screen tech for now) as a comfortable handheld reading device, it can easily supplant my iPad since it's more comfortable in every actual use case. I always want to put any device that big down, not hold it, and once it's sitting on something, the Surface is way more flexible in how it can be positioned. Let's face it, lying flat is actually a pretty awkward angle for a screen, and for the iPad anything else is an afterthought.
 
Surface Pro 3 is just brilliant. SP3's Kickstand is probably the best thing you can find on any tablet on the market today. Plus it has more than 4 000 000 regular Windows applications.