I can't afford photoshop so am looking around and trailing all the apps.

I'm really struggling with all of them really. They all either seem to lack important features or I'm just missing them, so i am here to ask for advice on these points:

I need to be able to blend, so i want a brush that is sensitive to pressure on the wacom. In either size and/or opacity. So, I've been playing around and so far tried Sketchbook Pro, Pixelmator and artrage. So far I can't seem to find a setting in any of them that allows that.

Am I blind or is photoshop the only one that can do opacity and/or brush size with the wacom's pressure sensitivity? Surely not?