Since my original post I haven't messed with greenstuff an enormous amount, but I'd say a lot of my attempts came out nicely. I haven't tried sculpting a whole model or anything that ambitious, but I can buy models I like anyway 
I have had great success making cloaks out of thinly rolled and torn layers and also using it to fill gaps on poorly designed models. I haven't quite found the right smoothing tool yet,(Did find a cheap dentist set of a metal pick, scraper and a mirror at the dollar store- the back of the mirror is my smoothing tool so far...) but I have used other textured elements to cover up areas that didn't smooth out.
For me, non-scented chapstick works to keep my tools and surface non-stick, and warm water helps to make the areas I'm working on softer. Chapstick does hurt the ability to stick two pieces of green together, but hasn't affecting the painting surface that I can notice. Thanks for the advice, and I'll keep at it
I have had great success making cloaks out of thinly rolled and torn layers and also using it to fill gaps on poorly designed models. I haven't quite found the right smoothing tool yet,(Did find a cheap dentist set of a metal pick, scraper and a mirror at the dollar store- the back of the mirror is my smoothing tool so far...) but I have used other textured elements to cover up areas that didn't smooth out.For me, non-scented chapstick works to keep my tools and surface non-stick, and warm water helps to make the areas I'm working on softer. Chapstick does hurt the ability to stick two pieces of green together, but hasn't affecting the painting surface that I can notice. Thanks for the advice, and I'll keep at it