I type a lot [Laptops, Keyboard phones, but not Tablets]
The difference between typing on a Keyboard Phone w/Thumbs [SGH-T699, LG F3Q, etc] and everything else is where/how you can type. With Thumb Typing & a force rotation app, you can be laying sideways in bed == more comfortable positions.
Laptop and Tablets require you to be sitting up and certain Tablet keyboard addons make your Tablet require a hard surface to the flimsy 'keyboard case' design ...even though the device is a "Mobile" Device.
Thumb typing on a tablet is terrible and usually works best with 4" phones and