Advantage to IGH , no derailleur to mess up .


lots of posts about D problems in the Mechancs section .

commuting, yours may have been bumped/ banged in the bike rack
bent derailleur hangers throw off the whole click shifting thing .


its foolish to be adjusting the stroke limit screws an expect the shifting to improve.

you may need a real bike shop for the in person demonstration, you have a CoOp in town to use?