The software is not that bad. It just has some limitations. Depending on your point of view and your expectations, they may be major or minor.
The biggest thing to understand right off the bat is that the Glowforge software/app/web site simply doesn’t do much. It’s not a full-fledged design program like Silhouette Studio. It’s more like a print preview window. You have to do all of that work in another program and just load it into the Glowforge app to place it and select options for material type, cut settings, etc. Personally I’m hoping it evolves into a more capable program that lets you at least draw basic shapes, but for now be aware that the workflow is 90% in another program.
The next friction point comes from the interaction between your drawing program and the Glowforge app. At the best of times, it’s slightly tedious. Export from here, save, go over there, upload, find the file, open. If it doesn’t come out right or you want to make an adjustment, repeating this can get really boring really quickly. There are a lot of details in the way vector files are constructed that means what you see is not necessarily what you get. You will have to deal with combining paths and grouping and outlining and fill vs. stroke and rasterizing and embedding and exporting to SVG with the right units. It could be argued that this has nothing to do with the Glowforge software, but at least some of the prep you have to do in your art program is to avoid features that aren’t supported or to work around bugs and design flaws details in the app.
Sometimes you upload the file and get a vague error. Sometimes it works on the second or third try for unknown reasons. Sometimes the Cloud is down, or at least that’s your best guess because other people on the forum are complaining and it starts working again later. Sometimes it’s the file: you may or may not figure out what’s wrong with it, but you need to change it in some way before GF is happy with it. A few of these are specific issues that tell you what the problem was. Most don’t.
Now we get into the UI itself. As has been described endlessly, the camera is out of focus and out of alignment. How much depends on your machine and how much you care depends on you. Positioning, resizing, and rotating things can only be done by eye. As has been described endlessly, there’s no option to type in how big or where you want a thing to be. Your best bet is to make it the right size in your art program. If you’re using the wrong browser (even a supported one like Safari), you will experience error messages and incorrect behavior until you give up and use Chrome. As has been described endlessly, the manual settings are confusing and in undocumented, non-linear units.
Sometimes you try to select or drag and thing and end up moving the wrong thing, or just part of the thing that you thought was a group of things. Undo mostly works here. Sometimes you click print and you get an error. Maybe the cloud is down. Maybe your file is too big or too complicated. The error message doesn’t say, so if this happens, you have to experiment. Hopefully you didn’t enter too many settings, because you’ll have to start over to upload a new file. Sometimes you’re forced to reload and lose your settings anyway. When it does work correctly, you click print and wait quite a white for the scanning to happen, then wait quite a while for the processing to happen.
There’s no concept of a project, so if you do have multiple parts you’ve arranged in the app and settings you’ve applied, you can’t save them to recall later. What you do get is a sort of library of previously uploaded files, but whenever you open them, they are in their default configuration. You can’t group or organize these files in any way, so scrolling back through them all is a pain.
I think I’ve described just about all the ways I’ve seen it do something wrong or annoying. Like I said at the beginning, it’s not that bad. If I wrote a similar list of the frustrations of using an iPhone, it would be ten times as much. For many of us, much of the time, it’s a matter of exporting a file, loading it into the GF UI, and clicking Print. The times when that doesn’t work are fairly well understood. We’ve learned not to touch the hurty things.