Adobe Illustrator over Inkscape. I thought I'd save some money and learn Inkscape but it's just too weird an un-intuitive, sometimes buggy too. Key combinations couldn't be mapped to work like Illustrator which I was used to, so it's frustrating to work with because you know what it should be able to do, but now to have to figure out what Inkscape calls the feature and what menu that might be in.
Same for Photoshop over Paint.NET or anything else. Photoshop is still the master at layered image manipulation for all sorts of things. I use it for Web/UI mockup designs, and for photo editing in some cases. Nothing else can do this as well, and again it's because I'm so familiar with it and it's key combinations and features. Plus, now the new AI features are doing way more than I ever thought possible, it's pretty impressive stuff really!
I mainly use Inkscape nowadays. If I need to design graphics for print I'm installing Illustrator again. While Inkscape is really competent today it's nowhere near Illustrator in usability or features.
Dealing with type or layers in Inkscape is a nightmare compared to Illustrator.
Don't know the last time you updated, but Inkscape layers got an overhaul in 1.2, released about a year ago. Still not perfect, but a massive upgrade from how they used to be