It's too bad you can't keep both, I have the nook classic and the nook color and they compliment each other fantastic. overall i actually enjoy reading better on my nook color mine, like most, is not glitchy, to Belle2Be if your's is glitchy then why not just swap out for a new one? Lemons are found in every electronic devices and products.
But to the OP I would weigh in how much more do you use one over the other. If I were you, it sounds like you would have more use for the 'extra" fun stuff you can use on the nook color more, so I would return the Kindle,(personally the whole button and layout of that device screams 1990's) and just wait for a while when you can afford to have another eink reader. Prices will come down and heck you keep an eye out the Kobo which is decent eink reader makes a solid budget choice, which I'm willing to bet will be below $100 before the end of spring.