Aside from keeping in mind what you’re going to use the microphone for, the polar patterns, the connector, and whether you'd want a dynamic or condenser microphone, there's not much else that you should worry about. Of course, the looks of the microphone will matter if you plan to use the microphone for your videos and it's going to be seen. You might want to invest in a microphone that is photogenic and looks great on camera. On another note, you might want to hide the microphone, which may mean that you should be using a smaller-sized one, or a lavalier microphone. If mobility is important for you, choose a lighter microphone that you can easily connect to your smartphone or laptop. Of course, there are some technical aspects that you might want to get into when you're choosing the best microphones for your needs. Some of these include: • Cartridge type, which will dictate the transducer used. The cartridge is responsible for converting sound pressure to electricity. • Frequency response, or the range of frequencies that the microphone will pick up. • On- and off-axis responses, or how the microphone would respond to sounds that are coming from the front and those that are outside of its polar pattern. • Sensitivity, or how well the microphone can convert sound pressure to voltage • Distortion at THD 1%, which will tell you at which sound pressure level the microphone's total harmonic distortion will be affected • Impedance, which should be lower than your preamp's rated impedance Of course, these are not every technical specifications that can tell you if a particular microphone brand is good or not. There's a lot more, and to fully understand these specifications, you can watch this video.