I have an account there too. Two problems for me there at the moment and they're both technical. I can't find a native mobile client for it (mobile web is ok but not ideal) and iirc it's written in PHP which is problematic. I think a reasonable answer is both.
I guess just from my experience with system administration over a long time. I've seen many problems (security, maintainability) in implementations in PHP - maybe it's not the language but the projects which choose it? Anyway, that's the association it has for me.