Pros and cons of FOSS
Pros
No need for virus software It is more difficult to write viruses and easier to spot them with FOSS. However, most malware now comes through web browsers; so the main advantage is not having to wait for virus software to do its thing.
No need to defragment drives FOSS filesystems are designed to minimise fragmentation and normally do not needdefragmenting.
Better recovery from crashes or power failures FOSS filesystems can normally recover from a crash or power failure in seconds with no loss of data; of course, this does not apply if the hard drive fails!
Quality software FOSS developers tend to take more pride in their work and to use it themselves. So most FOSS does more and is easier to use, though there are exceptions!
Updates and patches Updates and patches are released regularly to ensure that bugs or vulnerabilities to attack are avoided. Often they come as delta patches, that is, instead of reinstalling the whole program, the changed section of the program is inserted into it in situ — which takes a fraction of the time that reinstalling it would.
Configuration and customisation Configuration and customisation to suit the user’s needs tend to easier with FOSS. If the user does not have the skills to customise a program to their needs, they don’t have to ask permission to commission someone else to do it as long as they stick to the FOSS principles that underlie the software.
Support Support is free and available 24 hours a day through FOSS forums. These are normally staffed by volunteers who are more likely to know what they are taking about because they use the program themselves or are the developers of it.
Interoperability FOSS tends to work better with different types of software, in particular, legacy software —allowing you to retrieve data from older systems graphics — allowing you to work with almost any format and to convert between formats multilingual software — allowing you to mix any number of languages, live or dead, in the same document.
Growth Expansion is less of a problem with FOSS both because of its interoperability and because you do not have to buy new licences when you take on extra staff or volunteers.
Recycling legacy hardware You can use the latest software without needing to upgrade the hardware at the same time and you can recycle older hardware, typically as a server for a network, freeing up the newer hardware for users.
Cons
Installation it is difficult to obtain a computer pre-installed with FOSS; you normally have to install the software yourself.
Updates and new releases FOSS distributions (the equivalent of XP or Windows 7) tend to need upgrading every eighteen months to two years rather than every five years or more with most commercial systems.
Solid state drives Because newer FOSS filesystems update the drive more often to avoid data loss, they are more prone to wear out solid state drives; older filrsystems or the very newest have to be used on solid state drives.
Microsoft Publisher There is no support in FOSS for Microsoft Publisher; so if someone sends you a .pub file, you are stuck.
Games Games are available for Apple products which are built on FOSS but.less so for other FOSS based systems.
Apple products There can be difficulties interoperating with some Apple products — but this is a moving feast. So consult Google or the relevant FOSS forum for the latest information.
No intermediate databases While there are some simple FOSS databases along with spreadsheets which can double as databases like Microsoft Excel, there are no intermediate databases like Microsoft Access; you have to jump from a simple database or a spreadsheet to SQL.
Optical character recognition (OCR) There is no optical character recognition software to match the quality of proprietary OCR software.
Support Support can be variable and some forums are better than others but it is normally better than getting advice from someone who has never used the program and is reading from a crib-sheet.