@MarkG I have tried on two different occasions to keep a Bullet Journal but the first time I tried it I couldn't stick with it. I did a good job with sticking with it the second time, but I found the upkeep of it was taking away too much time. I was putting more time and effort into maintaining it than I was gaining from increasing productivity in return.
In general, any productivity system that works for you is the best one.
As mentioned, bullet journal is on a weekly/monthly basis, usually consisting of about 20 items per week and around 10 items per month. It takes about 20 minutes to setup the next week and about 5 minutes at the end of the day to update it / re-arrange stuff.
The best part of the bullet journal process for me is marking which planned items have not been done and need to be transferred to the next week. Eventually you can see some patterns on stuff you procrastinate on or just don't consider as important as initially thought (so it might be a good idea to drop it).