I am beginner drummer and I need to buy a V-drum. What makes a good v-drum? What should I look for to avoid buying a bad v-drum?
Electronic Kits have pros and cons, as with acoustic kits. The main thing you want to look for in buying a good E-Kit is when you sit down and start to play, that you are comfortable and it feels right. Usually the heads on a generic entry level E-kit, do not feel the same as an acoustic kit and far away from the actual feel, so you want to look for whether it makes you happy, sit down and have a little jam on it. Chuck some headphones in and just go crazy. if you feel happy after then it usually is going to be good for you. You should avoid low end E-kits, the more expensive electronic kits are usually the best bet for good quality hardware, electronics and just all round better to have, less repairs, less hassle. I'd recommend the Yamaha line of E-Kits, they are reliable. Ive been playing for about 10 years and I started on a Yamaha Electronic Kit and stayed on it for about the first 3 years of my drumming.
It's important to mention that electronic drum kits are not 100% silent. They're far more silent that an acoustic kit, but there may still be the noise of the drum sticks on the rubber and mesh pads.