Of course it's best to drive nails with a hammer, but more than once, growing up on the farm, we'd grab whatever was at hand. It turns out that a rock, a crescent wrench, and Vice-grips can all get the job done but usually resulted in dented wood, smashed fingers, and bent nails. So it is with presentation software. The best thing to do is to know the strengths and limitations of the different options and then select the best tool for the job.
For presentations, I use Keynote or Google Slides. The deciding factor on which to use usually comes down to whether or not I'm part of a group that requires asynchronous collaboration. I love the speed an fluidity with which I can make great looking slides, working with beautiful images in Keynote. But, if I have to collaborate with others who are building their own slides and we can't meet together to build one preso, Google Slides gets the nod. (Ideally, every presentation you give should be made in close collaboration so that the look of the slides is coherent - see this post by Keri-Lee for more tips on designing effective presentations)
When it comes to presenting, I love the presenter view in Keynote and the fact that I can roam around the room, see my notes, and advance slides from my iPhone. (n.b. you can also see a presenter view from Google Slides) Though you can present your Google Slides offline, embedded video will not play. Another thing that often plagues people presenting from Google Slides is laggy performance, especially for video when the wifi is questionable. For this reason, I like to make sure that for an important presentation, I control my own destiny and don't have to rely on wifi... I like all my media stored locally on my Mac (not an option in Google Slides).
After the presentation, Google Slides are super easy to share with others. If I decide to share my Keynote slides, it means an extra step to convert to PDF and then share with my audience. I love the design features in Keynote so much that it's my go-to for basic graphic design work as well and with a little extra know-how, you can use it to create amazing interactives for multi-touch books and even html5 web content. Not to be outdone, Google Slides is a great way to make dynamic headers and content for our online learning platform.
So you see, it depends. Here's a summary of some of the strengths of each software:
A lot of this honestly comes down to my own personal comfort and preferences. I'd love to hear your thoughts in the comments... are there other advantages or disadvantages you are thinking of? Not to mention PowerPoint... how does that fit into the mix? My hope is that you'll carefully consider your choice of tools and use the one that best fits your needs.