I've used both, and I cannot recommend that you go for wired strongly enough. If you get wireless that run over wifi and are monitoring or recording them with a computer or DVR, you are looking at a constant 5+ Mbps stream per camera bogging down your network. Also if you're comfortable running Ethernet, I would run that to each location and get a decent POE switch. Then you can get one UPS and centrally power everything, and upgrades in the future will be easy. I've had mixed results using one of those Ethernet over power line adapters to add a camera in a detached but powered garage. It will work for months at a time and then just up and crap out. Rebooting fixes the issue, but since the building i'm monitoring is a vacation home that can be unoccupied for weeks at a time, that doesn't really help me.
As far as cameras go, I've recently had excellent luck with Q-See best outdoor surveillance cameras
They make decent weatherproof cameras, I've got two currently mounted outside, one that keeps an eye on a dock (in the summer) and one that keeps an eye on the house year round. Both of these include IR lights and the quality is also quite good at night.
As far as viewing, I run BlueIris, it's a little bit of a resource hog but does the trick. There is a webpage I can access, android, and ios apps, and it emails me a 15 second video clip if motion is triggered on certain cameras. If you stick with one vendor (such as Q-see) you might be able to use their DVR and software, but since my installation has been a constantly evolving one with occasional camera upgrades, I like not being tied to a specific vendor.