My multivariate calc was a separate course from regular calc 1/2/3

Eh, really depends on the use case. For example if you want to edit something distributed in a psd format gimp won’t even tell you something got imported wrong. So the file will import but will look wrong.

And then there’s the UI. It just refuses to follow any current standards. Whether that’s a good or bad thing depends on the user.

Personally I use affinity photo. Works for my use case and is a one time purchase product, which for me is ok.