I was using a Samsung Galaxy Note 10.5 and Autodesk Sketchbook Pro, which was great but limited in function. I'm now using a Surface Pro 4 and Autodesk Sketchbook 8, or something. It's the same program just the actual desktop version of it, which had a huge amount of functionality. It's pretty much Photoshop without the crazy price tag. With free brush downloads once a week, which is really cool. Because I bought it I've actually got three different versions of the same program, so it's great. If you want cheap, the Samsung Galaxy's have gone way down in price, they're somewhere between 150-350$, so it's pretty good. They're old, you can't get them in store so you'll have to go online. Definitely recommend, and they're a tablet too so they have other functions outside of drawing. The Surface Pro is definitely more expensive. Originally I got a Pro 3, which is cheaper but doesn't have the pen. The Pro 4 is something like 1200$, so if you're really serious, or if you need a portable computer and a drawing tool, the Surface is the way to go. Definitely awesome. It's all about what you want, really. Those are what I've used and I 100% stand by them.

Yeah I've looked at the pro 4. Ultimately I've told myself that I want it to be something that I only have to buy once so I'm gonna probably go with the Pro 4 around Christmas time