I own a 5 unit in a very bad neighborhood, but its generally a solid money maker.  

I would like to install surveillance cameras around the perimeter since they are cheap now and could provide additional security.  In your experience what are the advantages and disadvantages of installing security cameras, and should I use wifi or not?

In the past I have hard wired my surveillance equipment into a dedicated box at the house.  It is connected to wifi, so i can tap into it from my mobile device, when ever i want (although there is a short delay). I bought it from Costco and the box is secured in a locked room, so only I have access to it, I also have monitors set up in that room if i wanted to watch the screens or replay events.  I guess you need to ask yourself i you want to store the data you gather, or just stream it, or both.  The few hours of work it took to install mine has payed off, with a battery back up the system does not go down even with power outages, they would have to smash my cameras to stop the recording.

There may be legal issues though, if you are in a bad area where nefarious acts happen the police could take your system to conduct investigation.  I cant advise on that aspect.

Hey @Achi Adamit

I agree with wi-fi surveillance. But I recommend upgrading night lighting and "landscape security" (keeping your property well-groomed) as the first order of business. 

It's always best to deter and prevent... 

Mr Williamson is right,

Cameras, although much more advanced than in the past, also are very limited on what you can actually see.  I have 4 on a single family home, and it still leaves a ton of open area that cannot be viewed.  Also night recording and landscape is vital, just like he said.  

-->>> An additional piece of advice I thought of after my post, was that you should get a aerial photo of your property.  Print it out on paper, and do what I call a " terrain sketch ".  Identify your <Avenues of Approach> .  Identify where your <blind spots>  are.  Identify where your <Power> locations are.  

Extend out your Vision \  / Left and right lateral limits  and realize anything outside of them will not be on camera, and the further out you go the more degraded it will be.  

Cheers.