KSS1992,
I've tried 10 inches tablets with the ipega 9023, and I have to say that it is not very confortable to play and even a little to heavy. With the shield tablet and the ipega, I don't get tired.
If you want a good tablet with enought power to play everything, except dolphin (which runs half speed with most games), I will have to say that the shield tablet with ipega it's a great combination.
About portability, anything bigger than 5 inches is not very portable in some situations. But, if you carry around a shield portable or even a GPD g5a, you probably can't fit it in your pocket. However, if you use a backpack, you can carry any of this devices.
I also have a shield portable but, if I can, I always use the device with bigger screen. Unless the screen is so big that it's not portable anymore.