Create Log File To Track Progress And Populate Controls Via Text File Or XML File?

I am trying to create a log file which I am going to use to populate some controls (DataGridView or Treeview). I am trying to figure out if should use text files or XML files to do so. Effectively the log will highlight multiple phases in a client-side app. The log will be written to at various phases when the project is running. The user will always have the options move on to the next phase or save progress and exit the project. As such, I want the log file to highlight how far the user has progressed throught the various phases AND I want the log to highlight varous information from each phase. Whenever the user starts the project, they will be given the option to load existing log files. So the project will have to read these log files and append them where necessary as the user progresses.

I am not sure what the best way to do this is and below is a rudimentary approach using text files. As you can see, the top of the file would have a summary of all the phases and whether or not the user completed each phase. Next each phase would have a data section highlighting what data was stored along the way. I have used a ":" to denote each section. Then within each section I would obviously need to use a delimeter for all my data. So if Phase1 = True, then I would load all the pertinent data from "Phase1:" into the desired control. Can anyone provide an efficient way of doing this and provide some insight as to whether I should use XML instead. The phases my change during development and I am not sure yet which controls I will be using. Does XML provide more flexibility.

In summary I am looking to create, read/write and append log files and populate controls with the data in varous sections of the log file. Example:

Phase1 = True
Phase2 = True
Phase3 = False
Phase4 = False

[code]....