>>2264697Sai lacks the power and variety of tools that photoshop has, but it's surprisingly good drawing software, especially when you're starting out.
Photoshop is like having a giant toolbox filled with tools you have no clue how to use. You're just as likely to fuck up worse with it than you would with Sai if you're misusing things, but if you learn how to use it properly you can do things better and quicker than you might in Sai.
That said I find clip studio to be an excellent compromise between photoshop and Sai. It has more features than Sai, a few less than photoshop, but generally is more tailored for art rather than just photo editing.
Photoshop's lack of stabilizer makes it take a lot of time to learn how to make clean lines. Even if you can draw perfect ellipses on paper you'll probably get some blocky bullshit in photoshop. That's one thing that Sai and clip studio negate that's really important, and a reason lots of people sketch / ink their stuff in those programs then paint it / refine it in photoshop.
At the end of the day, though, some of it is personal preference. Neither is objectively better, though photoshop objectively provides greater utility. Try both, see what sticks.