Performance of various data merging methods

Recently I got the task to develop a Web Part which would aggregate the contents of a couple of RSS Feeds, sort them descending on the publishing date and display the top n of them. Thinking about how the whole thing could be done, I have found out that there are multiple methods to get things done. The Web Part was supposed to work on an Internet site so I decided to have a closer look at the performance of the various methods.

The first thing you notice is that the XSLT based approach is definitely much faster than other methods using DataTables. So if you have to provide a good performing data merging solution, you might want to check whether you are able to benefit of XSLT.