Storing data in cache vs in file storage in asp.net

We have a website which shows up, RSS feeds from multiple other websites owned by us, now we have 2 options to load RSS from live url:

1. Using .Net caching object to serve the latest feeds every 2 hours.
2. Using File based (Storing in xml form and reading using XmlDocument), pulling out latest feeds and saving it to file for 2hours and update the file after expiry, and displaying the content on the site from this file.

Can anyone suggest which would be the best method to implement.

My vote is for File based because with caching we are using the server resource for the next 2hours after which it will expire, but with file based we are reading the content from local file and showing it.