I have used a number of digital timers but returned to mechanical timer. Digital timers are quieter and more accurate, but programming is not intuitive, and reviewing what has been programmed is a pain, requiring pressing multiple buttons to desplay the digital info.
All Mechanical lose or gain time a little daily, but retiming or reviewing what has been programmed is straightforward, simply by advancing the wheel forward or changing the pin locations. Since the timer runs my CO2, I turn off the power strip of the timer to do water change weekly so I need to retimine weekly by simply advancing the wheel to match real time.
I like the old fashion mechanical that has red and green pins than the newer mechanical with infinite tabs to press. The newer mechanical is harder to read with my progressive lens, and wrong tabs can accidentally be bumped. Another key feature important to me in the old fashion is the manual overdrive that allows automatic resumption of programmed schedule.