Most tablets out there, the good ones, go for well over $200. VisTablet's vTen pad is cheaper than most, and you get more for your money. Compared to most other offname brands out there, VisTablet does an excellent job with their products, making them durable enough for travel.
It's only 6x4.5, but for screens under 19'', unless you're looking for more precision v.s. screen size, that's all you'll need. I love this tablet, and it works really well for the digital art that I like to do.
Of course, the software needed for actual creation of art work is more expensive than the tablet if you buy the professional versions, but there are some free alternatives for certain products.
VisTablet does a good job with the vTen pad, and it could be a lot more expensive for all you get with it. The pen that comes with if feels a bit cheap, but getting a differently designed pen is simple enough, and not very expensive.
Well worth the price I paid for it, and while it's not a "professional" tablet, you could probably get similar results if you know what you are doing.
I wouldn't recommend shoving this in a backpack though, it flops like a mouse pad, and needs a hard surface if you don't want to screw up. Shove it in a backpack without stowing it right and you could ruin it. (I haven't actually done that though, I don't want to have to pay for another if I don't have to.) However, if I did break this one, I would buy another one.
Also, the pen is cheap feeling, and breaks easily. You might want to replace it with the pen from the original Tablet from Vistablet.