There are 3 main factors that you need to consider when choosing a racket. Balance, stiffness, and price.
Balance: There are 3 different types of rackets. Head light, head heavy, and even balance.
Head light rackets are generally designed for beginners as it puts less strain on the wrist and is easier to move around the court. They are characterized by their speed and excel in drives, very technical shots, and defense. Power is generated by your arm.
Head heavy rackets are generally designed for more advanced players, as their technique and strength is developed to a greater degree allowing them to reign in the extra weight on the head without sacrificing shot consistency. They shine brightly in power and overhead shots such as smashes, clears, and drops. Power is generated by the additional momentum produced by the extra weight.
Recently, aerodynamic design has advanced to the point where the speed around the court of most high end head heavy rackets (the main weakness of these types of rackets) is no longer a significant hindrance.
Even balanced rackets strike a balance between. While smashes and clears may not be as effortless and powerful as head heavy rackets, they retain the defensive capabilities of head light rackets. They excel in superior shot placement allowing you to retain a greater control of the shuttle.
Flex: The spectrum of shaft flexibility and how it relates to your game is pretty straightforward.
Supple flex = More power
Because the racket flexes at the point of impact and holds the shuttle on the string bed longer, it allows for more energy to be transferred to the shuttle giving more power.
Stiff flex = More control
Because the racket flexes/moves less during your shot, however you hit it is however it’s going to fly.
Generally speaking, more advanced players use stiff flex rackets, as they already have enough power (presumably from physical training) and mainly want to focus on getting their shots to land exactly where they want them.
Price: Within each category of head balance, there are different rackets with different flex, and as such, there are also different rackets with different prices in each category as well. Higher end rackets tend to be made of a superior material and have a more advanced frame design, but in all honesty, the differences in an actual game will be small. Just choose the racket with a price that fits your budget.
I would like to conclude saying that (and you hear this alot for a reason) although there are many different aspects to choosing a racket, there is not necessarily one specific racket that is better than another. Go with what fits your playing style.
And as much as a good racket helps your game, at the end of the day, don’t expect that buying a $240 racket will drastically improve your game. The player holding the racket matters more than the racket itself.
Please keep in mind that choosing a racket is only 60% of what you use to hit the shuttle. The string as well as string tension you use are almost equally (if not equal) important as the racket.