Software, where to begin?
With questions obviously. What are you, Hobbyist or Pro? Designer or Image Editor/Photographer? Creation for output or for sharing files for edit?
Windows or MAC?
Do your research, invest in yourself, if your situation benefits from one platform or the other go for it, the learning curve does not last forever. There are software pluses and minuses to each operating system. Quality is not one of them!
Design Suites Parameters.
Design suites in my opinion give you vector drawing, image editing and page layout capabilities ion one package.
Professional Design Suites support the GDI (Graphics Device Interface) or what ever they call the new updates to it, I believe it's GDI+ as well as the MAC vesion of this interface. This feature allows the graphics applications to function with office applications and printers. A design suite must also support Postscript 3 and PDF, the ICC Color Management (International Color Consortium) as the base of core technology support. This technology allows support for professional output technology including all postscript and PDF including live transparency output. Professional Suites support the core color models of RGB, LAB, CMYK and Device N color intransparency at the least and in many cases many more color models.
Pro designers who share their work for others to edit.
Adobe is the most compatible as most users have it. The problem is that Adobe Illustrator many times makes files that only work in Adobe Illustrator, which really ticks people off if they want a to place complex Illustrator files in CorelDRAW, Inkscape or Publisher. Also layered Photoshop files really only work 100% of the time in Photoshop and many times only in the same version the file was created in.
Corel is just as capable but fewer users have it and again there will be sharing and editing issues, just more of them, it's a poor choice for this process.
Low cost options like Affinity or no cost option like Inkscape in my opinion are non starters for the most part because of a multitude of technical issues with editing there exported files in other applications. This issue becomes more apparent as the complexity of the file increases. Also in my experience much of the core technology support is limited.
Designers who output their own files or design their files output.
Adobe again is supported the most in print however that's where they stop having any advantage, if it is an advantage because many times support is very poor. Todays print shops are few in number and many are severely limited in knowledge.
Corel is just as capable for most print, by most I mean 99.5% they fall short on large page count documents but make up for it by being vastly superior for large and grand scale print, vehicle wraps, donor walls and signage up to 150 foot square, in 1 to 1 scale. However support is no better than Adobe.
Affinity or Inkscape will be as good as the user, as far as that goes so will MicroSoft Publisher but YOU THE USER have to be extra capable.
Image editing and output application parameters.
It's the same questions. If you're creating layered work for sharing and editing, you had better only share it with people using the same application. Not only the same application but in many cases the same version of the same application. Otherwise, it's not if there will be issues, it's, there will be issues. Also transparency from one application in many cases does not work if taken into another application.
With the concept of using a flattened TIF file (no layers or transparency) for inter application transfer most of the following will work fine. Photoshop, Corel Photo-PAINT, GIMP, Affinity Photo, PaintShop Pro and a host of others.
The things to look for in an image editor are ICC Color Management, LAB color model support, CMYK support, Device N color support, all these color modes supported in transparency. As far as I know the only ones with all of these features are Photoshop and Photo-PAINT. So all the other applications I know of have to religated to support positions if you have need for one or more of these features. If you're a pro working in a mixed environment you will need all these features.
What to look for in a RAW editor?
RAW editors are as numerous as the stars in the sky. I know a few people who use only the free Nikon RAW converter and they do fine with their Nikon RAW files.
In RAW editors, look to see if they support your cameras or your clients cameras. Key features in my opinion are conversion, batch processing and file management. The value of any other features only you can judge, I do not like the RAW converter image editor in one package concept, it tends to limit ones thinking but I understand it from managing an image editing house concept. I just thinkthat it's limiting.
What I use. Says it all, it's just what I use I make no endorcements.
AfterShot Pro has the core features I need in a RAW converter, it supports all the devices I need, it has file management, batch processing, Perfectly Clear, Denoise and a host of RAW editing capabilities. The tone curves are excellent, it too has many image editing featurs but I find either I'm used to my applications so they seem unintuative or maybe they are unintuative.
Photo-PAINT, it has an extremely sharp display for critical edits, document level color management, LAB, CMYK and Device N color all supported in transparency. It has an assortment of filters, great cloning and great masking capabilities that make it very viable for color correcting as well as great painting capabilities. Corel has not kept this application as modern as they should have.
PaintShop Pro has an assortment of features like 3 different 16 bit noise reduction filters, multiple 8 bit noisereductionfilters, chromatic abberation removal, lens distortion, depth of files filters to mention a few. It's designed for the hobbyist but it's quality is professional level and is very useful as the filters work well for many of the poor quality files I receive today. It's a great augmenting application for Photo-PAINT and AfterShot Pro, since using it I have no need for Photoshop. The issue is that it is application color managed, has no LAB, CMYK or Device N support so for professional work it has to team up with Photo-PAINT.
GIMP has only one use for me so far, it supports larger physcial page sizes than the Corel Products.
I also use AKVIS Mask for enhanced masking, Denoise for enhanced noise reduction and PhotoZoom Pro for up sampling. Professional level upsampling is a must have today as the use of APS-C cameras dominate the current photography business and they lack the resolution for large and grand format output.