These days I tend to prepare talks and lectures using two main bits of software; for lectures to undergraduates, I use beamer (a LaTeX based style for producing PDF presentations), and for seminars on my own work I use Keynote. So, it's been along time since I've had to fire up PowerPoint in anger. However, I've recently had to produce a talk in PowerPoint (for boring and complicated reasons), and the experience has reminded me why I fled to Keynote's open arms.
It's true that Keynote doesn't have all the features of PowerPoint. The drawing tools included in Keynote are very simple, but I just use OmniGraffle which works beautifully and is dedicated to producing graphics. You can either copy and paste graphics in, or import them, so it's very little extra hassle. There are also fewer options for building animations (though this has improved with the latest release), but I can't say that I find that a problem.
PowerPoint is agonisingly slow on my machine, with appreciable delays when moving between slides during editing, selecting text boxes and so on. When you move a text box it leaves visual debris of parts of the bounding box in place, which remains until you scroll the screen down and then back to that particular slide. Trying to change the size of text is maddening. It tries to 'intelligently' fit the text size to the size of the box1. What this means is that you choose 22 pt, and PowerPoint says "I think you meant 24pt" and changes the size. You then growl "No, I really did want 22pt" and change it back. Ad infinitum...
Then there's the maddening 'sort of there, sort of not there' fading Formatting Palette. Why not just make it hide and appear dynamically? Making it fade so that it partially obscures whatever is underneath it, but is too faint to be read properly is no good to anyone. I've also never got the hang of the expanding/collapsing sections in the palette either. The rule seems to be that the setting you want will always be in a collapsed section.
It will be a relief to go back to Keynote and beamer, which both manage to work properly without getting in my way.
1 Yes, I know that this is an option in the preferences, but I find it really irritating that it's on by default. And Microsoft Office applications often develop amnesia about my preferences. I've lost count of the times that I've told Word that I speak British English, thank you very much.