Yea, I really liked Photoshop when I started, but I realised later it's not that great, especially for starter like me - I was confused with brush settings, tools and there wasn't any smoothing for lineart and I can't draw very smooth lines without it yet - it's pretty hard.
And then I've seen some speedpaints using SAI and I gave it a shot and voila - much better than Photoshop and I was happy using it... Even the practice drawings are made in SAI.
Each to it's own.