I have the Tab 3 7" and pretty good.
According to my causing with the new Tab 4, they're about the same but he says the new one is better. I haven't play with the new one yet so I'm not sure.
But if I'm okay with mine, I guess the new one should be better.
Not neccesarily. I believe they have the exact same scree actually and a lot of things(at least on the 8.0 model) are actual a downgrade on the tab 4 series compared to the tab 3 series; like the camera and non lighting up buttons on the tab 4's amongst a few other things I can't remember right now. There are things however, like the processor speed which are upgrades on the 4 series.
Even with my sad 65 year old eyes I find even tiny script easy to read and colors suprisingly accurate. Lighted buttons on the Tab 3? Mine must have been defective because they never lit. I even turned off all saving functions and on every power suck I could find to test battery life and stamina and still had no lit buttons! That's okay, got my Tab 4 last week and sold my 3 yesterday.