There's actually some pretty big differences besides the levels of pressure sensitivity. The Bamboo doesn't have an eraser on the stylus and the Intous has tilt detection. I use the pen tilt for most of my brushes, and I'd strongly recommend saving up for an Intuos if you can. It's totally worth having the extra control. Oh, and do try to use the pressure sensitivity. It helps a lot with line quality.
I'll have my Intuos for sale as soon as I can get a Cintiq 12WX to replace it. Unfortunately I don't see that happening within the next few weeks so there probably won't be much that I can do. Are you currently a student? You might be able to get some pretty good deals on a new one.