I think between these two models of advertising. eg New York Times offers a banner / text link advertising - which is very simple and efficient since they have a lot of visitors. But I'm thinking that it might be better to write a sponsored article (maybe Digg), what do you think? How much would cost a sponsored article?
think aout who will be looking at the banner ad ptentially and who will be looking for an article \ either one could work but you have to write a very catchy headline I usually use abstract stuff related to my niche but in all reality completely off topic just to get somones attention ex. "Learn how to find the love of your life with ease" for a how to market online training program you have to be very creative and think about what will attract people first in a way that can be later applied to potential interest in your business
Sponsored article is more towards the lines of PPP (Pay Per Post), which doesn't really have a great ROI unless it's a highly targetted niche and/or very popular site. There are plenty of free alternatives to PPP in which you can create hubpages or write an article, and submit to article directories such as Ezine, Buzzle, etc. Some articles have received thousands of views. As far as banner advertising goes, it's not a fair comparison since they are much different. One is more along the lines of PPC, while the other is brand building mixed with SEO (link building) efforts. Best of luck Matt