EC225
As far as I am aware the only into service issues have been a requirement to modify servo's and update VMS software to overcome a density/altitude limitaiton and some recurrent cracking in the tailboom on non-stress bearing structure. Both have been a bit of a pain operationally I believe but aside that its no worse than any new aircraft entry to service.
Pax & crews seem to like it. Oh, and its got nice big windows...