Yeah, I used mouse all the time until i bought a tablet. Here are the difference of quality by using a tablet :
Lineart ; Using a mouse and pen tool will create a clean perfect lines, straight or curved. It's click click click and computer does the rest after all. Perfect for drawing mechanical and structure. Now if we're talking about quality, there is 1 thing missing :
Pressure. Pressure gives "feel" to your lineart. It is a simple logic that when a line gets light from any light source, the line should look thinner, and vice versa.
Wait, i didn't say pen tool (photoshop) cannot do that, in a difficult way however. It is easier in SAI and EVEN much more easier using a
tablet . The drawback is, actually the opposite of using mouse, you will have
VERY hard time drawing clean ad perfect line using tablet. For me example, drawing a simple line for face took more than 10 times erase & draw
. The line got jagged and distorted, though this is depends on your hand's stability ( when you're not used drawing, your hand tends to shake, or if your hand got any medical problem )
Painting ; This is a very obvious thing. Using a mouse to give a simple cell shading for your drawing is actually difficult. Assume you want to paint a face, The step is, you need to paint the face, doesnt matter if the paint got beyond the line, you will need to erase it later anyway. This "erasing" thing, for newbie in painting, will took a lot of time because you need to zoom, select the size of your eraser and carefully erase.
OR you can do it using much simple method by masking the area you want to erase using pen tool/lasso tool.
That was just 1 part, the next part is you need to paint darker color aka. shading. Note that most of hair shading ended in a very pointy areas where you need to change brush size many times. My point is, while you took
1 minute for change brush size, paint, change again, when it reach pointy areas, erase a bit ;
tablet can do those in 1 second thank to its pressure control.
And guys, here is my advice : even though you mastered mouse technique and comfortable by using it, you need to learn using tablet as soon as possible. Most professional artist out there didn't even use a mouse. All they need is a few layers and a tablet. Most reason is : better productivity. This is applied for drawing characters though, while drawing building and mechanical, I think mouse still rules (even better if you do it using 3D).
ps : hey i'm back, how r u guys, sorry for leaving you for almost a year. College things got wild and I need to waste my time study and study. Its over finally, in the beginning of February, I'll be back active.