This little dojobby's going to take some getting used to.
I'm trying out the Windows port, and seems very promising. A little buggy, but haven't run into anything major.
One thing I've noticed from the start, and I know I'll need is brush sized cursors. So far, I've only seen the option of either "Tool Icon", "Tool Icon w/ Crosshair", and "Crosshair Only". These are ok ... but it's an immense help knowing exactly what portion of your image is going to be affected by a brushstroke, before you actually make that brushstroke. (ie: in Photoshop, if you choose a 100px brush, the cursor changes to a 100px circle, and you can position it more accurately when making a brushstroke)
Is there anything in GIMP that will do this ... or perhaps a plug in available? I haven't checked the various plug in resources yet, so I dunno. Will get to that eventually though.
AbecX ... being the only person I know who actively uses GIMP ... Help a brotha out?