Hi Ripbab, and welcome to this great forum. I think you did the right thing and now you will see that your (photographic) life will be positively impacted by the IV... I own a GRDIII and I simply love this camera, having it always with me... My Nikon D200 is getting full of webs
. I use Aperture 3 when at home and I'm quite sure I worked on some RAWs from the GRDIII, in any case I find it's jpegs very good, so in practice I always shoot in this way and save a lot of space on my disks... Traveling a lot and being far from home for long time I also use a iPad to pp my shots, in particular Snapseed and Autostich... Very simple and cheap and you can see the results in my posts
So enjoy your GRD IV and show us your pictures, we will enjoy them!