My last cruise on Emerald Princess was an obstructed view cabin. The lifeboat covered the bottom 1/4 of the window. Otherwise, there was still plenty of view, so in that case I would say the discount may be worth it. In cases where the entire view is blocked, I would think an inside with a comparable "view" would be a better choice.
Try to find a site that has pictures of your particular cabin in question. There is a site, but I unfortunately do not remember it's name. Try using the search phrase "cruise ship cabin pictures", or perhaps someone here can fill in the blanks.
Also, keep in mind that what I think important may be of minor concern to you, and vice-versa.