There are lots of things to consider which can help define which sort you want.
I have just tried to capture what I have learnt from our home grown installation which has been through a few revisions. If you want more detail on any of them you are welcome to ask or DM. Some of it is a bit of a ramble, sorry hope it helps.
Going for a general brand like SWANN is never a bad thing.
It gives you lots of options and add on's but even then there are many choices within the brands.
If you want a cheap chinese unit from amazon.eBay be prepared to geek it out a bit on setup etc. The menus and manuals are a little bit mickey mouse generally but they are good value and mostly work well.
I use S3VC which is a cheap but highly workable system -
https://www.amazon.co.uk/stores/node/19887521031 they appear to have stopped making the whole pack now but another similar one from another vendor -
https://www.amazon.co.uk/dp/B07PTYYX6C/?th=1 I have not used this model.
So what to select.
1. Some are old style analogue and use coaxial (like an old TV aerial cable) cable to provide power and data from the camera back to the box so need dedicated cables pulled.
2. Some are LAN/Network/IP based and use domestic WiFi or UTP/Ethernet/RJ45 cables.
Setup
The LAN/network cable ones need either a RJ45/UTP cable to form the network. The power can be fed down the same UTP cable with PoE (Power over Ethernet) from a switch or local power adapters (injectors) to reduce the cable pulling. The CCTV boxes will often include the PoE capability on the ports but it means you have to pull the cable all the way back to the CCTV box. With most of the cameras they will have an umbilical cord that comes into the house through the wall and this is a fair size (UTP & Power) so you need to drill a decent sized hole. You cannot feed it through the edge of the double glazing without damaging both in the medium term. Do look at this aspect of the camera before buying.
The WiFi ones just need a local power supply and the signal to the wireless access point clear enough to work. It depends on all the same problems as your home/laptop wifi. Location of the WAP/CCTV controller needs to be thought out. In general they have built in WiFi and you need to put them on another channel to your home WiFi box. Use channels 1,6 or 11 but nothing else. Put the home WiFi on 6 and the CCTV Wifi on 11. A 2MP camera needs about a 5Mb WiFi link. You can check this by placing your WiFi home AP near the CCTV box location and then moving your phone to where the camera will be (including outside the wall) and you should still get over 1/2 signal strength.
The analogue cable (co-ax) is actually easier to install with a smaller hole so makes less house damage during install so don't write it off! The cable is also cheaper and easier to seal.
Do be aware that the WiFi based systems can be subject to jamming/interference using cheap blockers bought on eBay etc so do not represent the best for real security. A mixture of cabled and WiFi for a garage connection would be advised if you go down the LAN option.
The controller box is generally HDMI output and possibly LAN/WiFi accessible. If you cannot see the pictures then it's not being very effective....... We have a spare iPad in the lounge which is connected over the WiFi to the CCTV box and uses a browser to see the picture. It needs an F5/refresh from time to time to catch up but gives us a simple view of the cameras. We have an older computer monitor/keyboard/mouse directly on the CCTV box for general use if needed.
Most of them offer a remote access via phone app and can send emails and SMS alerts to your phone if you go that far. It does take a good bit of fiddling so leave that until later.
Cameras can be classified into a few key features. These can be found with both the co-ax and LAN/IP connections.
Basic fixed camera (indoor, no LED probably)
Basic fixed camera (outdoor, LED's)
PTZ indoor (Pan-Tilt-Zoom or steerable)
PTZ outdoor (Pan-Tilt-Zoom or steerable)
Zoomable versions of the above or replaceable lens for different focal length.
WiFi ones allow you to install on/using power in the garage etc aso long as the signal back to the box is good enough which is useful.
The main recorder box needs a hard disc to store content and it is often not included, don't go mad on the size. If you have a four camera system using cameras about 2.0 mega pixels 1920x1080 or FHD 1-2Tb of disc will be fine unless you are paying a lot and lighting it very well. In general they have a 10-20 foot range unless you get special lens, similar at night. 3Tb disc will give you >1 weeks archive before content gets overwritten. 5MP cameras will more than double the requirement and data rate for the Wifi etc. Some of the disc vendors do "survelience or NAS" discs as special variants to allow constant running, yet to be proven but not a bad idea.
https://www.amazon.co.uk/Purple-3-5-SATA-6Gb-5400rpm/dp/B071RM2HS7 You can mix and match cameras in general. I would use a few fixed cameras and one or two PTZ around the door or entrance the flush dome style can be less obtrusive. You may want a long focus one to cover the drive front or if practical install one from the garage front. Don't run copper cable of any type from a garage to the house above ground. The camera/view/location is one of the most important bits as it will be a compromise of cable/access as well as picture quality. Plan on them being high up as the plebs are wise and spray or move them if they are low (think arm stretched and a stick) but low enough for catch a face not a hoodie/cap. Put one near the front door (fixed dome) so that the face is caught as they walk up to the door.
You can also get additional LED light arrays designed for the correct frequency for the CCTV which provide fill in or supplementary light to give better coverage at night.
https://www.amazon.co.uk/Infrared-Illuminator-Power-Camera-Security/dp/B01D73XMKG/ Use them in conjunction with traditional sensor lights mounted high up with a good power and throw (LED's reduce the power and weight). In many cases strong well placed traditional security lights with PIR sensors can be almost as good a deterrent. Again mount them up high and avoid blasting the neighbours!
https://www.amazon.co.uk/Security-MEIKEE-Floodlights-Waterproof-Equivalent/dp/B07HH3WPSKHope this helps. £250 plus some fiddling and geek hours give peace of mind but add the PIR lights would be my honest advice.
