I wrote like a whole 4 paragraphs explaining my views and tips and then internet crashed. So heres the synopsis-
Sai is lighter than photoshop and makes it more smooth to draw with a lower end processor. But lacks the good masks, colors, mixing, layer use, filters, addons and warping capability of photoshop.
Watch your aspect ratio, especially if you have multiple monitors and a tablet that jumps around the screen. (AkA if you have a 16 9 tablet and two 16 9 monitors the total is 32-9, making horizontal movement twice as slow, and vertical moment normal speed)
And I like to sketch with paper, but the tablet is just too good of an opportunity to use the great resources digital drawing has (AkA you never can lose progress, only gain it) , and I use my tablet for actual portfolio pieces and work I would show people.