Either one is better than nothing, however, you need to pick one or the other, and stick with it for the rest of the life of the car. Once you start flushing, stick with it. If you drop the pan and change the filter, stick with it. When you change from one to the other, you will start having problems. I suggest the replacement of the filter, it gives you a chance to see in the pan and make sure you aren't shaving the guts. But that is messy and takes time, so pick what you are comfortable with.
