It's a nice to have security surveillance system in your home or office. But before buying it - you must have to take into consideration some important points for proper selection as listed below:
1. What is your budget?
2. Indoor or Outdoor
3. Does it need Infra-red illuminator?
4. It must be weatherproof and/or vandal proof?
5. What is estimated viewing angle?
6. It's preferred style must be as dome, bullet, cube or no preference?
7. Where are you looking to store recorded footage?
8. How are you looking to power the camera? E.g. Power Over Ethernet or via wall mains etc.
9. Lastly, What accessories might you need? Like a specific mounting bracket?, POE injector or switch? SD card? An NVR or NAS?
And more other consideration as per your place and needs.