Most of the complaints about the software arise from features that used to be there but have disappeared, or never worked well in the first place such as the search mechanism. Upgrades were always promised but never delivered.
These things are not major problems but they do continue to hang on unfinished and add to the uncertainty of just how healthy the system really is, looking at it from the outside like we users do.
I've seen people complain about search not finding something many times. But every time I've done it works. I put that down to people not knowing how to search. They are too specific and include punctuation and other things that might vary.