With the price of computers dropping, in most cases buying from major suppliers will be more feasible. If you want to pick and choose your own components (i.e. graphics card, SSD drives, etc..) then building makes sense.  

If your computer is over 4 years old, it will be more desirable to get a new computer and transfer your data. Exceptions can be made when the software on old computer cannot be installed on the new unit due to compatibility or missing software licenses.

IP system is way to go these days. A single CAT5e or CAT6 can provided both power and data signals connected to a POE switch. You don’t have to connect cameras directly to NVR where under CCTV all cameras must connect to DVR.  There are other advantages such as picture quality and flexibly issues.

Make sure your internet upload speed is adequate. In most cases, the download speed is set to less than 1 MPS vs 15 MPS on the average. We noticed lately the internet providers in our area have bumped up the default upload and streaming is getting better. Also, make sure to select Sub Stream vs Main Stream on your remote device app or software.

Ease of access to your data and not worrying about the loss of data due to local server break down are key advantages. More and more customers moving their crucial applications (i.e. financial, email, backups) to cloud bases versions.   Cost of cloud services is one of the main complaints we get from the customers we migrated to cloud-based services.

If you want to access the latest Microsoft Office software along with cloud based exchange servers and easy email access from anywhere, then go with Office 365. Make sure to select licenses that fit your needs. Please keep in mind that all cloud based applications are internet based and if you are planning on working in areas with poor internet connection, then you may include local apps in your contract.