Are all the guitars the same?
No. There are many types of electric guitars available in the market. The right guitar depends on the sound that you are interested in. While some guitars can easily switch between jazz, blues and rock without any perceptible difference, the others cater to only one type of sound. Choosing the sound that you want will simplify your purchase decision. Besides, the sound you also need to take into account the location of the neck on the guitar. The two most common types of positions are the "set-neck" and the "bolt-on" necks. The set-neck allows you to keep on playing longer than bolt-on. The meeting point of the neck and guitar is tighter to allow the sound to move freely between the two.
You must also consider how to tune a guitar. It is very important that the guitar you want to buy is easy to tune and easy to play. Or else you will be left with a very cool electric guitar but enrolling yourself in a free guitar lessons for beginner.
What are frets?
You can choose the electric guitar based on how wide and long the neck is. 21, 22 and 24 are the number of frets that you can get with the usual guitars. The guitars from Stratocasters have 21 frets. This gives you a shorter neck but opting for large frets will let you play more easily.