The first vibrator decision is less about features and more about fit: where on your body you want sensation, how loud you can be, and what materials your skin tolerates.
Start with location
External (clitoral) versus internal (g-spot) versus dual-action are different shapes. If you've never used a toy, external is the gentlest place to start — most reviews suggest a small bullet or wand.
Then pick the material
Body-safe silicone is the modern default: non-porous, hypoallergenic, easy to clean. Avoid jelly or PVC if you can.
Quiet matters
If you live with people, look for "whisper quiet" specs. Most modern rechargeables are 50dB or under at full power.