Here are some images from the Kindle version (on an iPad) of Effective Perl Programming. It doesn’t look bad considering how bad most other non-novels look on Kindle, and its readable. These are two non-consecutive pages:
The paragraphs are nicely separated and it’s easier for you to see what is code and what isn’t. The images are decent, although they stand out against the grey background.
To compare Kindle to something I think is much better, here’s Pro Git on iBooks on an iPad. Again, these are non-consecutive pages:
Media Temple created the Pro Git ePub edition and it looks quite nice. They redid some of the images in color and obviously took pains to make it look good.
This isn’t to say that one reader is better than the other (although one is), but that it seems that all of the books I have read on Kindle pay very little attention to the presentation. When you’re presenting a novel, that’s not that important. With a technical work, it’s paramount.