Favorite rocket electronics and why?

Those who are pretty new to rocketry would appreciate some advice from those of you that have some experience. Please share your insight and experience about rocket electronics. If you can spread some light on the following question I’d appreciate it.

What electronics do you find useful for your launches? ie: Timers, Altimeters, etc.

What brands/models do you like?

What features draw you to those brands/models?

What would you consider the best application for a particular item? Ie: This altimeter is ideal for minimum diameter rockets.

What else am I missing that I should be thinking about?

Thanks.