< Resources

Software

It's either Photoshop or Clipstudio. Text tools in other programs just aren't there yet, because no one cares about text tools in image editing programs.

Photoshop

The go-to. If you've already got experience, stick with it, if you're new to image editing software it can be quite intimidating, but it'll be worth it. It even has scripts for scanlation. Check out the quicksandscans guide.

Clipstudio

Clipstudio used to be pretty great. So great that I felt inclined to actually purchase a license.
Not anymore. It constantly screams for a connection to the license server, and a "Lifetime License" is basically worthless now, because you need to PURCHASE A SEPARATE SUBSCRIPTION FOR UPDATES.
I regret ever supporting this dogshit company.

Anyways, the main advantage with Clipstudio is that many mangaka use this to draw their manga, so if you've got the patience to adjust settings for a while, you'll be able to replicate pretty much everything perfectly.
There is no scripting support, so you'll have to hack together your own external tools for it. I've got something written in AHK, but it's janky as all hell. I'll provide it on request, but don't expect me to help you with my spaghetti code.

The Rest

I wouldn't bother because the text tools of most of the alternatives suck ass. If you're already comfortable with Gimp or Krita, then sure, go for it. I just need to be able to edit my text directly, not in a separate pop-up window.