I've started a Bullet Journal. I've always kept a physical notebook to hand; sometimes it's more situation appropriate and easier than typing on a smartphone. It's primarily been somewhere to scribble down blog post ideas or to write out whatever was on my mind. I'm also really bad at task management apps. Other than when I use them to set a particular notification, I tend not to be very mindful about using them to plan… well, anything. I find that they're great for specific uses, like the groceries list, or for specific events that aren't calendar appointments where I might still want my phone to alert me, but anything else in there just gets forgotten about.
A Bullet Journal therefore kind of fits both uses. It's tangible enough that I pay more attention to it, and I can still use it for all the ideas and stream of consciousness nonsense that I have always used a notebook to capture. I still have apps available for those situations when they are more appropriate, too.
So far It's been enjoyable. Figuring out the page layouts (or "spreads") that work for me is kinda fun in itself, and having this procedurally based, almost programmatic, modular construction really works in a way that compliments the way my brain likes to build solutions. I'm using a slightly non-standard system with a weekly spread and an alternate notation based on the Dash/Plus system that works a little better for me (and is visually more appealing. The most immediately notable response to keeping the journal has been an acute awareness of how often I put tasks off, and which tasks they tend to be. Whether or not I can turn that knowledge into better habits remains to be seen.
There are a lot of people out there with beautiful and elaborate, well-decorated Bullet Journals, there are in fact entire Instagram accounts dedicated to this practice. I kind of feel that this runs against the goal of a fast system that allows you to be more productive at the things you want to do than a product of it's own. I also acknowledge that enjoyment alone is a perfectly valid reason to devote time to illustrating your journal, if that appeals to you. I haven't been as minimal as the basic Bullet Journal concept suggests, but I've kept to simple geometric partitions both in acknowledgement of my artistic talents but also to minimise the time requirement in maintaining the visual style.
I've previously owned Moleskine notebooks but I opted for the custom purpose Leuchtturm 1917 journal which is a better quality book but also has some of the layout work preprinted. People use all kinds of notebooks, and you can throw some money at this decision according to your tastes.