AdSense is much better than AdBrite in terms of earnings per click and ad relevance. However, I'd say AdBrite has the advantage of having a modest payout level (only $5) which means you get a quicker return than AdSense. It's also very possible to get 10-15 cents per click with AdBrite, plus it has the advantage of being less fussy than AdSense when it comes to your site design and content.
Best still is to use both AdSense and AdBrite inlines like I do. I can earn an extra 20-30% by using these inlines too. For more information check
my article about how well AdBrite is working for me.