A DVR, or Digital Video Recorder, connects to analog cameras.  These cameras must always be directly connected to the recorder. 

An NVR, or Network Video Recorder, connects to network cameras via ethernet cable.  Network cameras are powered by PoE technology, or Power over Ethernet.  It is often convenient to connect the network cameras directly to the PoE ports included in an NVR, but it is not required.  Network cameras can be connected to PoE ports on a separate network switch.  As long as the network cameras and the NVR are on the same network physically (and virtually if you want to go deep into the subject),  then the NVR can access the camera feeds and record the footage.

Both types of recorders have ethernet connectivity in order to make them accessible for viewing the cameras both locally and remotely.  To an end user, DVR's and NVR's function in exactly the same way.

Network cameras are much better.  Also, network cameras are more often referred to as IP cameras.  

As mentioned in the above answer to the previous question,  IP cameras merely need to be wired to a network port, and not always home-ran to the NVR.  Copper Ethernet wiring has a distance limitation of 100 meters.  Network cameras can be connected to a recorder than is in a separate building , hundreds of meters away, so long as they are physically on the same network.

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If you've ever edited a photo, you can relate to this example;  if you photo with the wrong camera settings, it's next to impossible to edit the photo to make it into a good image.   If you use the correct camera settings, the photo is good to begin with, and even better with simple editing. 

An IP camera has its own internal settings accessible through a web browser (each camera is of course password protected and encrypted) or through the NVR's user interface.  The optics of each camera can be individually adjusted to be better suited to the camera's environment.

One common setting that is often adjusted within an IP camera is called WDR, or Wide Dynamic Range.  This setting brightens shadowy areas and clears up high-glare bright areas, making the overall image more usable.  It's like a very advanced contrast reduction adjustment, but with physical optics involved.  The camera then sends a good image to the NVR, and the NVR can do more with that image, like detect motion more accurately.

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Many IP cameras also can have added analytics or even AI that is not possible for analog cameras.  An example of these analytics would be human versus animal distinction or vehicle detection. 

Analog cameras can be installed using old coaxial CCTV wiring, so HD analog camera systems are still a great option for upgrading older systems.

The equipment cost for network cameras and DVR's is also less than that of NVR's and IP cameras.  This makes an analog system an entry-level option if the budget won't allow for an IP camera system.

In a wired CCTV system, the DVR or NVR will have a hard drive.  These hard drives are replaceable or expandable.  Upon specifying and ordering the equipment, a hard drive size is selected.  We recommend no less than 1TB of storage per 4x cameras when set up for motion-based recording.  In most cases, a system with 1TB supporting 4x cameras will last about 1-2 weeks before filling up and overwriting itself.  This is based on our entry-level 4 megapixel camera.  If using higher resolution cameras, such as 8 or 12 megapixels, more hard drive space will be required for the same recording duration.  If longer storage times are needed, again, more hard drive space should be added accordingly.

Hard drives are either installed from the factory, or by Amp AV technicians.

For a DVR or NVR camera system like Hikvision, Luma, LTS, or Illumivue, no, there are no contracts or fees.  Once you purchase the installed equipment, you own it, and you will never have subscription fee to access any footage.

For Ring, we prefer the X line of products, which includes a lifetime cloud services subscription for that device.  Again, no ongoing fees.  Standard Ring products that are not part of the X line will require a paid subscription in order to access recorded footage.

Ring and Nest cameras are also great, but not perfect.  We like Ring doorbells over Nest.  Specifically we like the Ring Elite doorbell models because they are flush-mounted and use a hardwired ethernet connection instead of WiFi.

One major downside to cameras like Ring and Nest is that if there's no internet connection, or a poor internet connection, they don't record.  The camera streams can bog down the upload bandwidth of the home.  This is especially detrimental to homes in more rural or remote areas with lower internet speeds.  

The dependence on internet upload speed also makes the resolution of cloud-based cameras far lower-quality and frame rate.  Their streams must be much more heavily compressed (down to about 1Mbps per camera) than the compression of a CCTV system with a recording appliance (about 10-25 Mbps per camera).

Furthermore, cameras like Ring and Nest are not recording 24/7 the way a traditional CCTV system does.  Even if the DVR/NVR is set to motion record (usually that's the case to conserve storage space so it lasts longer before being overwritten), it is still recording everything.  It will dump any footage that does not include a motion-triggered event.  If there is an event, the recorder will save the footage starting from roughly 5 seconds prior to the motion detection.  This is extremely advantageous.  Cloud-based recording devices sometimes start the recording when the subject is already in the middle of the frame.

At Amp AV, we recommend a combination of cloud-based recording products and a wired CCTV system.  We prefer Ring for video doorbell products.  Our customers enjoy the notifications provided by the ring doorbell, but also the recordings of their wired CCTV system for more detailed playback information.  They also have peace of mind knowing that even if their internet service provider has an outage, the cameras are still recording locally to the DVR or NVR, and they are protected.

In short, no.

The products we install are professional grade, and we have the support of our manufacturers to rely on if needed.

Box camera sets have extremely poor technical support, but often require a LOT of technical support.

Simply put, we don't want to handle the installation of products that we don't support.

We do not offer installation of Ring doorbells as a stand alone service.  We normally only install video doorbells as a small part of a larger home technology installation project.

Floodlight cameras require installation by a duly licensed electrical contractor, as they are powered via 120V AC .  Our low voltage license does not allow us to perform the floodlight camera installation.

*Updated Q4 2022

NDAA stands for the National Defense Authorization Act.

CCTV products manufactured overseas or with foreign components must be NDAA-compliant in order to be installed in any government facilities, or the facilities of companies with government contracts.  Hikvision products (and Hikvision OEM's, includeing some LTS and Luma products) are not NDAA compliant due to Hikvision having a Chinese national interest.

If NDAA compliance is a requirement for a given project, Illumivue is an NDAA-compliant option, as is the Pro-VS line of LTS products.