Been using QGIS for about 6 years now for doing manual data analysis, as well as GDAL and Spatialite in C++ for creating/saving datasets and geopandas, Shapely, pyproj, etc for automated analysis.
QGIS is an odd duck. Part of the complexity of using it is the fundamental complexity of GIS software. There’s way more background info that I didn’t know (what do you mean a latitude and longitude doesn’t mean anything without a bunch more info?!) that’s necessary to use it effectively. All of the excellent UI in the world won’t save you if you’re not using the right coordinate system.
On the other hand… yeah, it definitely could use some love. I consider myself in roughly the amateur power user category. I don’t use it every day, but when I do fire it up once or twice a month I’m doing some heavy data analysis with it. Every time I do that I end up tripping over three or four things that seem like they should be obvious to do but aren’t. And man oh man… if there was a single bug I would love to fix: highlighted points, whether selected through the selection UI or through the data table… should always have a higher Z-order than the other points around them. The fact that you can select a bunch of points and not see them highlighted… so frustrating. You can go in and change the symbology to fix that in a number of ways but dammit it should work right out of the box. /rant