I brewed with extract for 25 years before I went to all grain. The reason it took so long was due to time constraints. I raised 3 kids, worked a lot, had a lot of house and yard projects, and brewing time was at a premium.
Once the kids were older, I had more time. I was brewing a partial mash beer one day when I began thinking about why I brewed at all. The answer was because I enjoyed the process, and it was a hobby. This prompted me to start all grain brewing, regardless of the time commitment, and I have never looked back. I love the process, the control, the feeling that I am using the same process that brewers have used for what, a thousand years?
So, for all the reasons listed by other posters, I say sit and think about why you make beer. The answer to that question will guide you to what process you use to make it.