Hi! I used photoshop in making comics, until i decided to experiment with Manga Studio EX4 which my friend lent me. I've never tried Manga Studio Debut.
What's your purpose in looking for a photoshop type software? to edit pictures? or to make comics? or do you have anything else in your mind?
In my experience of using MSEX4, it's primary purpose is to make manga/comic. it has the necessary tools a traditional mangaka would need. However, you can also make comics in photoshop, but your tools would be different.
MSEX4 takes time to learn, and so does Photoshop. If you're considering of making a comic, you could try MSEX4. if you want to edit pictures, go for photoshop. you can also try GIMP, it's a program which is also similar to photoshop.
YES, a tablet does make a difference! The mouse can't emulate the pressure and stroke depth when your using a tablet. If you're going to make a comic, then yes, it will make a difference. if your purpose is to edit pics, i'm not sure if it will also make a difference. . ..