Debating whether or not an electric instrument pickup is better than the other comes down to personal preference. Quality of a pickup however is generally universally accepted as being given to a company with many years of experience. Seymour Duncan, DiMarzio, Bill Lawrence, Fender, Gibson, EMG, TV Jones and Lace Sensor are the most well known and respected pickup companies in the market. There is a reason that these companies are famous and it comes down to two things. Personal preference on sound and the quality and consistency of the pickup brand.
Whether you are a serious player or an amateur, finding your own sound is as enjoyable and informative as finding your first guitar. Every pickup has its own flavor and every guitar bonds with a pickup in a different manor. Depending on how many pickups and what electronic controls will be attached to each pickup, you can have a plethora of sounds at your disposal or just one consistent tone. Whatever you are looking for in a sound, there isn't a pickup that won't help you on your way to achieving the sound in your head.
This post will talk about the match up between an active pickup and a passive pickup and what are the benefits and negatives from each. Hopefully I will help you narrow down the sound you are looking for and give you some insight into the market of pickups.
A passive pickup is a magnetic pickup directly sending the signal from your string, through the wood, into the pickup and into the amp which creates the most dynamic, organic sound you can produce. Many artists prefer a passive pickup to be able to have a "breathable" sound coupled with using their volume knob enables a multitude of tones without adjusting gain or treble on the amp. The negative aspects however with a passive pickup are it's feedback especially when gain from the amplifier is introduced as well as a magnetic pull on the strings which can cause intonation problems that reduces the sustain of the guitar overall. A single coil pickup found on stratocasters and telecasters generally produce a large amount of feedback and hum which is why the humbucker was invented to increase power over a single coil sound and to dampen noise feedback in the process. Jeff Beck, Darrell Abbott, Eddie Van Halen and Jimi Hendrix are prime examples of passive pickup users.
An active pickup is powered by a separate battery stored on the guitar enabling higher output and overall balanced frequency. Many artists who are looking for a consistent sound such as in metal music use Active pickups to achieve a powerful and consistent tone without compromising quality. Player's like Kirk Hammett and Kerry King use active electronics which enable them to push their amps near their limits and still retain a tight and focused clarity in their sound. The negatives of this style of pickup is the need to replace the 9v battery when the power supply is fading as well as being sterile in sound by critiques around the pickup community. An active pickup will generally sound the same no matter if the guitar is of solid body, semi hollow body, string through or with a vibrato bridge but generally speaking, a maple neck and alder body will always produce a higher and more percussive sound than a mahogany guitar.
So why is there a debate over pickups at all? It all boils down to preference as I was saying before. Pickups are just one part of the chain that links your guitar to your amp and eventually the sound coming to your ears. My advice is to try out an active pickup and passive pickup in similar built guitars and to shape your own opinion on the debate. Find out the different makes of each type of pickup through your local music store and build an wall of sound that defines the player and personality that is you.