Most of our projects at RoboticsBrno are powered either by Li-ion cells or 12V power sources. However, most of our servos and boards require either 5V or 3V3 power source.
We used to buy cheap stepdown modules from Aliexpress to do the job. They are inexpensive but their performance is questionable. Also, it is always a surprise what you get in the envelope – some batches of them operate better, some of them worse. One day, we decided to stop wasting our time with poor-performing modules and we designed our own custom module – the RB0005 Universal Stepdown.
To quickly distinguish our projects at RoboticsBrno, e.g., when ordering, we decided to give a each project a unique code.
We aim for usability. Usually, you need to lower your voltage to 5 V (servos) or 3.3 V (powering MCU) in DIY robotics. Having an adjustable version increases the chances of misconfiguration.
Well, it depends on your needs. If you need a certain level of reliability, it might be beneficial to know what to expect from your device. With our stepdown, you know it: see evaluation of the 5V version or the the 3V3 version. You could buy a module from Aliexpress and measure it by yourself. However, that is laborious and you cannot be sure that you will get the same-performing module when you order it again.